The time at which the two boats get closest to each other is t=21.6 min
What is meant by time?Time and work are concerned with how long it takes a person or a group of people to finish a task and how effectively each of them completes it.
Given that,
A boat leaves a dock at 2 : 00 pm and travels due south at a speed of 20 km/h.
And another boat has been heading due east at 15 km/h and reaches the same dock at 3 : 00 pm.
At 2:00 pm,
t=0
At 3:00 pm,
t=1
Distance=Speed*Time
D=15(1)
D=15km
Now, if the speed is 20km/hr
D=20(t)
D=20t
C²=(15-15t)²+(20t)²
(C²)'=2(15-15t)(-15)+2(20t)(20)
(C²)'=-450+1250t
(C²)'=0
Then,
-450+1250t=0
t=9/25 hr
(C²)'=-450+1250t=0
(C²)"=1250>0
Therefore,
t=9/25 hr
t=21.6 min
The time at which the two boats get closest to each other is t=21.6 min
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While spinning down from 500. 0 rpm to rest, a solid uniform flywheel does 5. 1 kj of work. If the radius of the disk is 1. 2 m, what is its mass?.
While spinning down from 500. 0 rpm to rest, a solid uniform flywheel does 5. 1 kJ of work. If the radius of the disk is 1. 2 m, its mass will be 28.33 kg
Work done = change in kinetic energy
kinetic energy = 1/2 * I * [tex]omega^{2}[/tex]
since , moment of inertia of disk = m[tex]r^{2}[/tex] / 2
kinetic energy = 1/2 * m[tex]r^{2}[/tex] / 2 * [tex]omega^{2}[/tex]
5100 = 1/4 * m * [tex]1.2^{2}[/tex] * 500
mass = 28.33 kg
If the radius of the disk is 1. 2 m, its mass will be 28.33 kg
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a swimming pool of width 9.0 m and length 12.0 m is filled with water to a depth of 3.0 m. calculate pressure on the bottom of the pool due to the wate
The pressure on the bottom of the pool due to the water is 22540pa.
What is density?
A substance's density determines how closely it can be packed. The definition of it is the mass per unit volume. The formula for density is D = m/V, where D stands for density, m for mass, and V for volume, which stand in for the object's mass and volume, respectively.
What is volume?
Volume is simply the quantity of space that a three-dimensional solid occupies. One of these solids can be a cube, a cuboid, a cone, a cylinder, or a sphere.
volume of water : 10*8*2.3m³
mass of water = density of water*volume
1000 kg/ m³* 1.84 m³
184000 kg
force extracted by water on the bottom surface = mass of water xg
=184000 kg * 9.8m/s²
=1803200N
pressure : force / area
1803200N/80m²
=22540Pa
Therefore, pressure on the bottom of the pool due to the water is 22540pa.
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Derive an expression for the mass ms of the star in terms of b, t, and g the universal gravitational constant.
The change in gravitational potential energy stored in 16 Jule.
What is gravitational potential energy?
gravitational potential energy
In classical mechanics, of the gravitational potential at in a location is equal to the work per unit mass that's would be needed to Move an object to that locations from a fixed references location. It is analogous to the electric potential with the mass playing the role of charge.
Sol-As per the given question ∆PE = mgh
M= skg
g= 4m/s^2
∆h = 2m
∆PE = 2m×4m×2m
= 16 Joules.
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a circularly-polarized antenna is designed to receive a rhcp wave traveling in the z direction. it consists of two wire antennas, one oriented in the x direction and one oriented in the y direction. the signals are combined from each antenna with a 90o phase shift between the two antennas, so that the total open-circuit voltage that is received is
The total open-circuit voltage that is received is 19.41V.
Solution:
RCHP traveling in the z-direction
E = E₁₀ cos(wt - βz) + Ey₀ sin(wt - βz)
E = [tex]\sqrt{E_{y0}^{2} + E^{2} y_{0}[/tex] = [tex]\sqrt{E^{2}_{O} } +E^{2}_{O}[/tex] = [tex]\sqrt{2} .Eo[/tex]
= [tex]\sqrt{2} Eo = 19.41 = Eo = 19.41[/tex]
Open circuit voltage is the voltage difference measured between two terminals when no current is being drawn or supplied. Short-circuit current is the current that flows when the voltage difference between terminals is forced to zero. No current flows in the circuit, but there is a voltage drop between the two points.
As a result, in an open circuit, the current through it is zero but the voltage is present. The current becomes zero and the power equals VI. When an open circuit is introduced, current flow through the circuit is interrupted. The voltage drop across each resistive element is zero when no current is flowing. However, the source potential difference appears to be open.
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Typically what percentage of a block of wood will be submerged if placed in water? Take the density of wood to be 103 kg/m^3. O A. Cannot be determined. B. 49.7 % C. 24.7 % D. 10.3 % Click Save and Submit to save and submit. Click Save All Answers to save all answers. Save All Answers
It will be 10.3% (D) of a block of wood will be submerged if placed in water based on the density of wood given.
Density is the substance's mass per unit of volume. The symbol most often used for density is ρ.
How to calculate the block of wood percentage that will be submerged in water?
Density of water = 1000 kg/m³
Density of the wood = 103kg/m³
If V be the volume of the wood and x be the volume of the wood inside the water then
Vρwood*g = Vρw*g
[tex]\frac{x}{v} = \frac{103}{1000}[/tex]
Percentage of volume of the wooden block submerged in the water is
[tex]\frac{x}{v}*100 = \frac{103}{1000} * 100[/tex]
= 10.3%
So 10.3% will be the percentage of a block of wood that will be submerged if place in water, and the answer is D.
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Consider a person of weight w standing in an elevator that is accelerating downward. An upward force n is exerted by the elevator floor on the person. The relationship between n and w is.
W-weighted person standing in an escalator that is descending quickly. The person is subjected to an upward force of N from the elevator floor. (Reply N=W.)
What does an elevator do?A vehicle that travels in a mine shaft to transport people or cargo between floors of a multi - storey building is an elevator, also known as a lift. The majority of contemporary elevators are moved by electric motors through a network of cables & sheaves with the help of a counterweight (pulleys).
What makes it an elevator?The word "elevator" is really the name of the a lift manufactured by a firm in the US. People began to refer to elevators as elevators since the company was just so successful and put them in so many locations.
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#SPJ4Describe how to determine wether or not an atom is boron
Answer:
has 5 protons and the atomic numb is 5
Explanation:
atomic number = protons number
they're equal
Answer:An atom consists of a central nucleus that is surrounded by one or more negatively charged electrons. The nucleus is positively charged and contains one or more relatively heavy particles known as protons and neutrons.
Explanation:
Which term found in the electromagnetic spectrum is determined by its wavelength?.
Color is the term found in the electromagnetic spectrum is determined by its wavelength.
Radio waves, gamma-rays, visible light, and all the other elements of the electromagnetic spectrum are electromagnetic radiation. Electromagnetic radiation can be defined in phrases of a movement of mass-much less particles, called photons, each visiting in a wave-like pattern at the velocity of light.
Wavelength is the space from one point on a wave to the same point on the subsequent wave. Frequency is the range of waves that skip through a factor in a 2d. Chemistry Interaction of light with count number.
The wavelength of light is an essential property for it's miles this that determines the character of the light. pink light has a distinctive wavelength to that of blue mild and green mild has a specific wavelength from each of them.
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A box of mass 3 kg is lifted 1. 5 m onto a shelf. Calculate the change in its gravitational potential energy. The gravitational field strength is 10 n/kg.
A box of mass 3 kg is lifted 1. 5 m onto a shelf. The change in its gravitational potential energy is 45 Joule.
The change of gravitational potential energy is equal to the work done on the box.
ΔEp = W
Where:
ΔEp = change of gravitational potential energy
W = work done
W = F x d
Where
F = force
d = distance
From the problem,
F = 3 kg x 10 N/kg = 30 N
d = 1.5 m
Hence,
W = 30 x 1.5 = 45 Joule
Therefore, the change of the gravitational potential energy is:
ΔEp = W = 45 Joule.
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The kinetics of the decomposition of phosphine at 950 k was followed by measuring the total pressure in the system as a function of time. The data in the table were obtained in a run where the reaction chamber contained only pure phosphine at the start of the reaction.
Select the rate law that best explains this reaction: Rate = k we discovered that the dissociation of phosphonate occurs in the first order, which exhibits the linear relationship between the pressure and time.
Phosphonates: Are they harmful?People are only slightly to moderately toxic to phosphonates. If phosphonates are consumed, they are quickly removed from the body through feces because they are not swallowed up either by digestive system. Due to the limited likelihood that phosphonates will build up in the body, ingestion through the epidermis is similarly unlikely to be harmful.
Where does phosphine come from?On Earth, Jupiter, plus Saturn, scientists have found the chemical molecule phosphonate. It is made up of three hydrogen atoms and one phosphorus atom. It happens frequently on gas giants alone, when both of the atmospheres are drenched in hydrogen.
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can someone help me scale this into a smaller one in cm?
The resultant displacement of the bullet is 1,418.6 m.
What is the resultant displacement of the bullet?
The resultant displacement of the bullet is the total displacement of the bullet obtained by resolving the displacement into x and y component.
the horizontal component of the displacement (x) = d cosθ
the vertical component of the displacement (y) = d sinθ
where;
d is the displacementθ is the directionFor the first displacement;
x = 850 m x cos(0) = 850 m
y = 850 m x sin(0) = 0
For the second displacement;
x = 640 m x cos(36) = 517.8 m
y = 640 m x sin(36) = 376.2 m
Net horizontal and vertical displacement;
∑x = 850 m + 517.8 m = 1,367.8 m
∑y = 376.2 m + 0 = 376.2 m
The resultant displacement of the bullet is calculated as;
d = √(∑x² + ∑y²)
d = √(1,367.8² + 376.2²)
d = 1,418.6 m
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A ferris wheel has radius 5. 0 m and makes one revolution every 8. 0 s with uniform rotation. A person who normally weighs 670 n is sitting on one of the benches attached at the rim of the wheel. What is the apparent weight (the normal force exerted on her by the bench) of the person as she passes through the highest point of her motion?.
As she crosses the highest point of her motion, the person appears to weigh 460 N.
What is meant by apparent weight?In physics, an object's apparent weight, which reflects its actual weight, is a characteristic. When an object's force of gravity is not counterbalanced by a normal force that is equal to but opposed to it, the apparent weight of the object will differ from the actual weight of the object. An object's weight is equal to the strength of the gravitational force pulling on it by definition.
Given,
The radius of the wheel, r = 5.0 m
Time, t = 8.0 s
And the weight of the person, W = 670 N
The following formula is used to determine the person's apparent weight as she crosses the highest point of her motion:
R=m(g-a)
Let the mass of the person is,
m=W/g
m=670/9.8
m=68.37kg
Now, we have to calculate the acceleration of a person,
a=(ω²)r
a=((1rev/8s)×(2Πrad/1rev))×5m
a=3.08 m/s²
Therefore, the apparent weight is calculated as follows:
R=68.37(9.8=3.08)
R=460N
As a result, the person appears to weigh 460 N as she crosses the highest point of her motion.
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problem 7-16 determine the internal normal force, shear force, and moment at points c and d of the beam. given: w1
The internal Normal force is equal to
The internal Shear force is equal to
Moments at points between C and D is
Internal Normal force :
The normal force at any section of a structure is defined as the algebraic sum of the axial forces acting on either side of the section.
Shear force:
The shearing force (SF) is defined as the algebraic sum of all the transverse forces acting on either side of the section of a beam.
Bending moment
The bending moment (BM) is defined as the algebraic sum of all the forces’ moments acting on either side of the section of a beam.
let Ax and Ay be horizontal and vertical component of A .
we have given that W₁ = 200 N/m × 6 m = 1200 N
and W₂ = 1/2 × 200 N/m× 6m = 600 N ( for triangle)
the distance between B and W₂ (x₂) = 1/3×6 = 2m
the distance between B and C (x₁) = 1/2×6 = 3m
Forces act in horizontal direction (Fₓ) ,
summation Fₓ = 0 = > Aₓ= 0
now, for vertical direction as Ay act upward and W1 and W2 acting downward direction.
summation M = 0
=> - Ay × 6 + W₁× 3 + W₂× 2 = 0
=>- 6Ay + 3600 N-m + 1200 N-m = 0
=> -Ay× 6 = - 4800 => Ay = 800 Nm
As we know total sum of force acting free body
= 0
=> Aₓ + N꜀ = 0 where N꜀ is normal force on C
but Ax= 0 so, Nc = 0
for Shear forces , Summation Fy = 0
=> Ay - W₁ - W₂ - V꜀ = 0 , where V꜀ is shear force
V꜀ = 800 - 200× 3 - 200 × 3/2 = -100 N
sum of moments Mc = 0
=> M꜀ - Ay ×3 - W1 × 3/2 - W2×1/3 ×3 = 0
=> M꜀ - 2400 - 1200× 3/2 - 600 × 1 = 0
=> M꜀ = 4.8 kNm
Hence , Internal Normal force is zero
shear force is 100 N and moment of force between C and D is 4.8 kNm.
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How does the angle at which a ray of light strikes a pane of window glass compare with the angle at which it passes out the other side?.
The angle at which a ray of light strikes a pane of window also called angle of incidence is always equal to the angle of reflection i.e. the angle at which it passes out the other side.
What is angle of incidence?
In Physics, on a plane mirror, there is a point of incidence at which the ray of light falls and returns to the same medium after reflection along the normal. as a result of this, an angle is formed which is called angle of reflection. While the angle formed between the normal point and the incident point is called angle of incidence.
Simply put, angle of reflection and angle of incidence are equal to each other.
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if highest high tide occurs at 2pm on day 1, at what time of day will the next highest high tide occur?
The height between high tide and low tide is referred to as the tidal range. tides are the peaks and valleys in sea levels brought on by the gravitational pull of the Moon, Sun, and Earth's rotation.
Tidal range is influenced by time and place. When the gravitational pulls of the Moon and Sun are in harmony, spring tides (spring range) occur, which have a larger tidal range. 0.6 metres (2 feet) is the average tidal range in the open ocean (blue and green on the map on the right). This range increases significantly closer to the coast at gravitational, there are several different coastal tidal ranges that range from almost zero to over 16 metres (52 ft).
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A lightbulb is wired to a variable resistor. What will happen to the color spectrum emitted by the bulb as the resistance of the circuit is increased? explain.
The color spectrum emitted by the bulb as the resistance of the circuit is increased is red.
Rt - Ro = 1 + α ΔT
Rt = Final resistance
Ro = Initial resistance
α = Coefficient of resistivity
ΔT = Change in temperature
Rt - Ro ∝ ΔT
Therefore, resistance is directly proportional to temperature.
As resistance increase, temperature also increases. As temperature increase, the molecules will vibrate faster and the wavelength will be shorter and the frequency will be higher. Since red has the shortest wavelength in the visible spectrum, the bulb will appear red.
Therefore, the color spectrum emitted by the bulb as the resistance of the circuit is increased is red.
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The slope of a straight line displacement - time graph indicates
Answer: velocity
Explanation:
Your slope is calculated as [tex]\frac{y_{2}-y_{1}}{x_{2}-x_{1}} =\frac{displacement}{time}[/tex], which equals velocity.
suppose you had a beam that is 1.51.5m in length and you place a fulcrum .25.25m from the left end of the beam (assume the beam is massless). you have a block of mass 77kg and you place it .3.3m from the right end of the beam. what is the torque on the beam?
The torque on the beam calculated from the principle of moments is 68 N to the right.
What is the torque on the beam?The torque on the beam is calculated using the principle of moments.
The principle of moments states that the sum of the clockwise moments is equal to the sum of the anticlockwise moments about a fixed point for a system in equilibrium.
Moment = force * perpendicular distance from the fulcrum
Taking the left end of the beam as the anticlockwise direction ad the right end of the beam as the clockwise direction:
Anticlockwise moment = F * (0.75 - 0.25)
Where F is the balancing force
Anticlockwise moment = 0.5f
Clockwise moment = (0.77 * 9.8) * (0.75 - 0.3)
Clockwise moment = 34 J
0.5 F = 34
F = 68 N
Hence, torque is 68 N
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a quarterback throws a football while standing at the very center of the field on the -yard line. the ball leaves his hand at a height of and has initial velocity assume an acceleration of due to gravity and that the vector points down the field toward the endzone and the vector points to the sideline. the field is in width and in length. determine the position function that gives the position of the ball seconds after it is thrown. the ball is caught by a player above the ground. is the player in bounds or out of bounds when he receives the ball? assume the player is standing vertically with both toes on the ground at the time of reception.
To learn the acceleration and velocity to find the solution.
What is acceleration?
The rate at which the speed and direction of a moving object change over time is known as acceleration. Any movement, whether straighter, faster, or slower, is referred to as acceleration. The fact that the direction is constantly shifting causes motion on a circle to accelerate even though the speed is constant.
What is velocity?
The velocity of a body or object determines the direction of its motion. Speed is often measured as a scalar value. The most basic definition of a vector quantity is velocity. It gauges the rate at which a distance varies. It relates to the speed at which displacement is altering.
Initial height = 6ft
initial velocity v₀= 41i+3gj+27k
assume upwards, as +k acceleration
due to gravity= -9.8m/s²k or
=-32ft/s² k
initial height (s₀)= 6k
position of the ball, after t secs
s= s₀+v₀t+1/2a₀t²
s=6k+(41i+3gj+27k) t+1/2(-32k)t²
r(t)=s=41 i+3gtj +(27t-16t²=6)k ⇒ 1
If the ball is catch by a player 6A above ground
s=6k
so comparing with equation 1
6=27t-16t²+6⇒ t(27-16t)=0
t=0 and t=27/6k =1.6875sec
at t=1.6875sec
from equation 1 r(1.675)=s=69.1815i+65.8125j+6k
so( 69.1875, 65.8125,6)
So he is in bound after he catches the ball.
Therefore, he is in bound after he catches the ball.
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A 325 kg boulder falls straight down from a cliff. The force of gravity
pulling it downward is -3185 N, while the force of air resistance acting
upward is +370 N.
Find the net force on the bolder then use 'Fnet = m a' to find its
acceleration.
F₂=3185/
Answer: -8.66 m/s2 (down)
Explanation:
Find the mass of the boulder:
F = ma
m=F/a = -3125N/9.8 m/s2 = 325 kg
F net = -3125 N + 370 N = -2815 N
now you can find a:
a = F/m = -2185 N / 325 kg = -8.66 m/s2
Please help me out with these questions! Really need help Thanks!!
2.a) The two reason of using isotope of gamma radiation over isotope of alpha radiation is:
Gamma radiation is neutral in nature where alpha radiation is positive in charge. So, charges of alpha radiation can harm human organs.Penetrating power of alpha ray is less than gamma ray. So, alpha ray may reflect inside the body and cause harm.b) i) According to the graph, the radioactive isotope remains inside left kidney for a long time period and it comes out from right kidney after some time.
ii) Only right kidney works properly because in left kidney the radioactive material remains for a long time which is not natural.
c) i) half life time of a radioactive material is a time in what the material decays into half.
ii) Short half life means the radioactivity of the material remains for short time which is less harmful for patient. So, doctor use it.
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a cyclotron with dee radius 48.0 cm is operated at an oscillator frequency of 13.0 mhz to accelerate protons. what is the kinetic energy of a proton emerging from the cyclotron?
The size of the field needed to create resonance is
= [tex]2\pi fmp/q[/tex]
= [tex]2\pi (12.0X10[/tex]⁶)([tex]1.67X10[/tex]⁻²⁷kg)
= 0.787T.
What is Kinetic energy?
A particle or an item that is in motion has a sort of energy called kinetic energy. When work, which entails the transmission of energy, is done on an object by applying a net force, that object acquires kinetic energy.
Therefore, the Kinetic energy is given by
K = 1/2 mv²
= 1/2m[tex](2\pi Rf)[/tex]²
= 1/2[tex](1.67X10[/tex]⁻²⁷kg)4[tex]\pi[/tex]²(0.530m)²(12.0X10⁶Hz)²
= 1.33X10⁻12J
= 8.34X10⁶eV.
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3 problems Mark Watney Face In The Martian and how he solved?
Answer:The first major problem Watney faces is getting stranded and wounded on Mars. The second problem Watney faces is how he is going to survive on mars till help can come. The final problem he faces is how is he going to get to the Ares, so he can leave Mars.
Explanation: I'm not too sure if this was what u were talking about but hope it helps!
an electron-volt (ev) is the amount of energy needed to move a single electron from an electric potential of 0 to an electric potential of -1 v. the charge of an electron is approximately -1.602 x10-19 c. how many joules is an electron volt?
The joules carrier by an electron volt will be = 1.602 x 10-19 J
What do you mean by electric potential?
Electric potential can be defined as the amount of work which is needed to move an unit charge from a reference point to a specific point against an electric field.
It can be calculated by the given formula
V=kQ/r or V = k Q / r . It is a scalar quantity while the electric field is a vector.
Uses of Electric Potential.
Potential energy a test charge would have at a given location due to a source charge.An incandescent light bulb that is turned off. To measure light and heat energy.Hence, in the above question the joules carrier by an electron volt will be = 1.602 x 10-19 J.
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what is a mass of 400ml of liquid that has a density of 4g/ml
Jocelyn estimates that a piece of wood measures 5. 5 cm. If it actually measures 5. 62 cm, what is the percent error of jocelyn’s estimate?.
The percentage error of Jocelyn's estimate is 2.135%
Estimated measurement of wood by Jocelyn = 5.5 cm
Actual measurement of wood = 5.62 cm
error value in calculation = 5.62-5.5 = 0.12 cm
Percentage error = (estimated number - actual number) / (actual number) * 100 = (0.12/5.62)*100
= 2.135 %
What is percentage-
% in mathematics is a quantity or ratio that is stated as a fraction of 100 Although the abbreviations "pct.", "pct.", and occasionally "pc" are also used, the percent sign, "%," is frequently used to indicate it lacks dimensions and has no associated unit of measurement.
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A sarcomere that is at a resting length of 1. 7um will generate __________________ force compared to a sarcomere at 2. 15um.
A sarcomere will produce its greatest amount of active force at a resting size of 1. 7 um rather than 2. 15 um.
Sarcomeres: what are they and what do they do?Sarcomeres are referred to as the basic contractile unit or muscle fiber. The two main protein filaments that make up each sarcomere and are responsible for triggering muscle contraction are myosin and actin. The most popular idea cited to explain how muscles contract is the hypodermic needle theory.
The Function of Sarcomeres
Muscle cells can be observed to have stripes-like striations under a microscope. This pattern is made up of a collection of basic muscle tissue units called sarcomeres that are stacked one on top of the other.
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A baseball player hits a ball straight up into the air. It leaves the bat with a speed of 120 km/h. In the absence of air resistance, how fast would the ball be traveling when the catcher catches it?
The speed of ball when the catcher catches it is 120km/h.
Speed is the rate of change of displacement with respect to time.
In this case, if the acceleration is constant, use the third equation of motion to determine the initial and final velocities.
The third equation of motion is
v² - u² = 2gS
where v---> final velocity
u---> initial velocity
g---> gravitational acceleration
S---> height
Given Data:
Initial Velocity of the Ball (u) = 120 km/h
Initially the ball is moving up, so the acceleration of the ball is g = - 9.81 m/s²
The final velocity of the ball is v = 0 m/s
The height of the ball above the ground can be calculated by using above formula
0 - (120×5/18 m/s)^2 = 2× (-9.81 m /s²) × S
=> S = 56.7 m
When the ball is above the hit point, the initial velocity of the ball at this point is u = 0 m/s.
Using above relation we can calculate the final velocity,
56.7 × 2 × (9.81) = v²-0 = v²
=> v² = 1112.45 m/ s => v= 33.45 m/ s
or v = 120 km/h.
Therefore the velocity of the ball when caught by the catcher is 120 km/h.
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the magnetic field strength at the north pole of a 2.0- cm -diameter, 8- cm -long alnico magnet is 0.10 t . to produce the same field with a solenoid of the same size, carrying a current of 2.0 a , how many turns of wire would you need?
Magnetic field - You would need N = 3032 of wire.
What is a magnetic field?
The magnetic influence on moving electric charges, electric currents, and magnetic materials is described by a magnetic field, which is a vector field. A force perpendicular to the charge's own velocity and the magnetic field acts on it when the charge is traveling through a magnetic field.
As seen in the following equation, a solenoid's magnetic field is
B = μ₀ n I
where n is the turn density, I is current and has a permittivity in a vacuum of 4 107 N/A2.
Let's use this equation to solve the issue; in this case, the length of the magnet is the unit of length, and the turn density is the number of turns per unit length.
L = 8 cm = 0.08 m
Let's compute.
B = μ₀ N/L I
N = B L / μ₀ I
N = 0.10 0.08 / (4π 10⁻⁷ 2.1)
3,032 103 turns,
Hence, the number of turns is 3032.
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A train travelling along a straight track starts from rest at point A and accelerates uniformly to 20m/s in 20 s It travels at this speed for 60 s, then slows down unformly to rest in 40 s at point C . It stays at rest at C for 30 s ,then reverse direction , accelerating uniformly to 10m/s in 10 s , it travel at thos speed for 30 s ,then slows down uniformly to rest in 10 s when it reaches point B.
a , plot a graph of the motion of the train
b , use your graph to calculate
1, the train's displacement from point A when it reaches point C
2 , the train's displacement from point A when it reaches point B
3 , the train accelerate each time its speed change .
The train's displacement from point A when it reaches point C = 1800m
The train's displacement from point A when it reaches point B =1800m
The train accelerate each time its speed change =1 m/s² and -0.5 m/s²
a. Plot of graph is mentioned in the image .
b. Now from the plot -
To find the train's displacement , we have to compute the areas under the curve .[tex]Area \\of\\Triangle = [ base * height ]/2\\[/tex]
[tex]S= [ 20 *20 +60*20 +40*20 ]/2 = 1800 m[/tex]
These are the sums of the areas on the graph from t=0 to t=120.
2. Since the train was at rest from point C till point B, the displacement remains the same -
S=1800m
3. To calculate the value of acceleration:-
[tex]0 < t < 20 ---------- > a= 20m/s / 20 s =1m/s^{2} \\[/tex]
[tex]80 < t < 120-------- > a=-20ms^-1/40s =-0.5m/s^{2}[/tex]
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