The English Channel is 35 km wide at its narrowest point, which is where most swimmers attempt to cross north to south from England to France. The current across this portion of the English Channel runs at about 2 km/h east to west.
a. If a swimmer has a relative velocity to the shore of 3 km/h north to south, how long will it take her to cross the 35 km distance?
b. What must be her velocity relative to the water if she has a velocity of 3 km/h north to south relative to the shore?
Answer:
a.) 20.4 h
b.) 3.46 km/h
Explanation:
Given that an English Channel is 35 km wide at its narrowest point, which is where most swimmers attempt to cross north to south from England to France. The current across this portion of the English Channel runs at about 2 km/h east to west.
a.) If a swimmer has a relative velocity to the shore of 3 km/h north to south, The resultant velocity (Vr) will be achieved by using Pythagoras theorem
Vr = [tex]\sqrt{2^{2} + 3^{2} }[/tex]
Vr = [tex]\sqrt{4 + 9}[/tex]
Vr = [tex]\sqrt{12}[/tex]
Vr = 3.46 m/s
To get how long it take her to cross the 35 km distance, Let us first find acceleration by using third equation of motion.
[tex]V^{2} = U^{2} + 2aS[/tex]
Where U = 0
Substitute all the parameters into the equation
[tex]3.46^{2} = 2 x a x 35[/tex]
11.97 = 70a
a = 11.97/70
a = 0.17 km/h^2
The time can be found by using equation
V = U + at
let U = 0
3.46 = 0.17t
t = 3.46/0.17
t = 20.35h
b. What must be her velocity relative to the water if she has a velocity of 3 km/h north to south relative to the shore?
her velocity relative to the water will be
Vr = [tex]\sqrt{2^{2} + 3^{2} }[/tex]
Vr = [tex]\sqrt{4 + 9}[/tex]
Vr = [tex]\sqrt{12}[/tex]
Vr = 3.46 m/s
A 0.111 kg hockey puck moving at 55 m/s is caught by a 80 kg goalie at rest. With what speed does the goalie slide on the (frictionless) ice? a 3.78 m/s b 2 m/s C 0.076 m/s d 1.056 m/s
Answer: 0.076 m/s
Explanation:
Momentum is conserved:
m v = (m + M) V
(0.111 kg) (55 m/s) = (0.111 kg + 80. kg) V
V = 0.076 m/s
After catching the puck, the goalie slides at 0.076 m/s.
A 0.111 kg hockey puck moving at 55 m/s is caught by a 80 kg goalie at rest. With speed does the goalie slide on the ice is 0.076 m/s
What is speed?The speed of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit of time; it is thus a scalar quantity.
Momentum is conserved:
m v = (m + M) V
(0.111 kg) (55 m/s) = (0.111 kg + 80. kg) V
V = 0.076 m/s
After catching the puck, the goalie slides at 0.076 m/s.
A 0.111 kg hockey puck moving at 55 m/s is caught by a 80 kg goalie at rest. With speed does the goalie slide on the ice is 0.076 m/s.
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the inside surfaces of the glass inside thermos bottles are coated with aluminum to prevent energy transfers by
Answer:
radiation heat.
Explanation:
That is any heat that passes through the air, like the sun.
Answer:
radiation
Explanation: I’m sure
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A block of mass m=2.20m=2.20 kg slides down a 30.0^{\circ}30.0
∘
incline which is 3.60 m high. At the bottom, it strikes a block of mass M=7.00M=7.00 kg which is at rest on a horizontal surface, (Assuming a smooth transition at the bottom of the incline.) If the collision is elastic, and friction can be ignored, determine the speeds of the two blocks (v_mv
m
and v_Mv
M
) after the collision.
Answer:
[tex]v_m \approx -4.38\; \rm m \cdot s^{-1}[/tex] (moving toward the incline.)
[tex]v_M \approx 4.02\; \rm m \cdot s^{-1}[/tex] (moving away from the incline.)
(Assumption: [tex]g = 9.81\; \rm m \cdot s^{-2}[/tex].)
Explanation:
If [tex]g = 9.81\; \rm m \cdot s^{-2}[/tex], the potential energy of the block of [tex]m = 2.20\; \rm kg[/tex] would be [tex]m \cdot g\cdot h = 2.20\; \rm kg \times 9.81\; \rm m \cdot s^{-2} \times 3.60\; \rm m \approx 77.695\; \rm J[/tex] when it was at the top of the incline.
If friction is negligible, all these energies would be converted to kinetic energy when this block reaches the bottom of the incline. There shouldn't be any energy loss along the horizontal surface, either. Therefore, the kinetic energy of this [tex]m = 2.20\; \rm kg\![/tex] block right before the collision would also be approximately [tex]77.695\; \rm J[/tex].
Calculate the velocity of that [tex]m = 2.20\; \rm kg[/tex] based on its kinetic energy:
[tex]\displaystyle v_m(\text{initial}) = \sqrt{\frac{2\times (\text{Kinetic Energy})}{m}} \approx \sqrt{\frac{2 \times 77.695\; \rm J}{2.20\; \rm kg}} \approx 8.4043\; \rm m \cdot s^{-1}}[/tex].
A collision is considered as an elastic collision if both momentum and kinetic energy are conserved.
Initial momentum of the two blocks:
[tex]p_m = m \cdot v_m(\text{initial}) \approx 2.20\; \rm kg \times 8.4043\; \rm m \cdot s^{-1} \approx 18.489\; \rm kg \cdot m \cdot s^{-1}[/tex].
[tex]p_M = M \cdot v_M(\text{initial}) \approx 2.20\; \rm kg \times 0\; \rm m \cdot s^{-1} \approx 0\; \rm kg \cdot m \cdot s^{-1}[/tex].
Sum of the momentum of each block right before the collision: approximately [tex]18.489\; \rm kg \cdot m \cdot s^{-1}[/tex].
Sum of the momentum of each block right after the collision: [tex](m\cdot v_m + m \cdot v_M)[/tex].
For momentum to conserve in this collision, [tex]v_m[/tex] and [tex]v_M[/tex] should ensure that [tex]m\cdot v_m + m \cdot v_M \approx 18.489\; \rm kg \cdot m \cdot s^{-1}[/tex].
Kinetic energy of the two blocks right before the collision: approximately [tex]77.695\; \rm J[/tex] and [tex]0\; \rm J[/tex]. Sum of these two values: approximately [tex]77.695\; \rm J\![/tex].
Sum of the energy of each block right after the collision:
[tex]\displaystyle \left(\frac{1}{2}\, m \cdot {v_m}^2 + \frac{1}{2}\, M \cdot {v_M}^2\right)[/tex].
Similarly, for kinetic energy to conserve in this collision, [tex]v_m[/tex] and [tex]v_M[/tex] should ensure that [tex]\displaystyle \frac{1}{2}\, m \cdot {v_m}^2 + \frac{1}{2}\, M \cdot {v_M}^2 \approx 77.695\; \rm J[/tex].
Combine to obtain two equations about [tex]v_m[/tex] and [tex]v_M[/tex] (given that [tex]m = 2.20\; \rm kg[/tex] whereas [tex]M = 7.00\; \rm kg[/tex].)
[tex]\left\lbrace\begin{aligned}& m\cdot v_m + m \cdot v_M \approx 18.489\; \rm kg \cdot m \cdot s^{-1} \\ & \frac{1}{2}\, m \cdot {v_m}^2 + \frac{1}{2}\, M \cdot {v_M}^2 \approx 77.695\; \rm J\end{aligned}\right.[/tex].
Solve for [tex]v_m[/tex] and [tex]v_M[/tex] (ignore the root where [tex]v_M = 0[/tex].)
[tex]\left\lbrace\begin{aligned}& v_m \approx -4.38\; \rm m\cdot s^{-1} \\ & v_M \approx 4.02\; \rm m \cdot s^{-1}\end{aligned}\right.[/tex].
The collision flipped the sign of the velocity of the [tex]m = 2.20\; \rm kg[/tex] block. In other words, this block is moving backwards towards the incline after the collision.
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We can reduce the force in collisions by extending the ____ of impact
Answer:
An impact which stops a moving object must do enough work to take away its kinetic energy, so extending the distance moved during the collision reduces the impact force.
Explanation:
A balloon drifts 140 m toward the west in 45 s; then the wind suddenly changes and the balloon flies 90 m toward the east in the next 25 s. a. What distance did it travel during the first 45 s? b. What distance did it travel during the next 25 s? c. What total distance did it travel? d. What was its average speed during the first 45 s? e. What was its average speed during the next 25 s? f. What was its average speed for the entire trip? g. What was its displacement during the first 45 s? h. What was its displacement during the next 25 s? i. What was its total displacement?
Answer:
Explanation:
Given
1 ) 140 m west in 45 s .
2 ) 90 m east in 25 s .
a )
distance travelled in first 45 s = 140 m
b ) distance travelled in next 25 s = 90 m
c ) Total distance travelled = 140 m + 90 m
= 230 m
d ) average speed in first 45 s
= distance in 45 s 45
= 140 / 45 = 3.11 m /s
e ) average speed in next 25 s
distance in 25 s / 25
= 90 / 25 = 3.6 m /s
f ) average in entire trip
= total distance / total time
= (140 + 90) / ( 25 + 45 )
= 3.28 m /s
g )
displacement in first 45 s = 140 m towards west
h )
displacement in next 25 s = 90 m towards east
i )
total displacement = 140 - 90
= 50 m towards west .
Bird man is flying horizontally at a speed of 30m/a and a height of 69 m. Bird man releases a turd directly above the start of the field. How far from the start of the field should the robot hood the bucket to catch the turd?
Answer:
The distance is [tex]d = 112.5 \ m[/tex]
Explanation:
From the question we are told that
The horizontal speed is [tex]v_x = 30 \ m/s[/tex]
The height is [tex]s = 69 \ m[/tex]
Generally from kinematic equation we have that
[tex]s = ut + \frac{1}{2} gt^2[/tex]
Here u is the initial velocity of the turd in the vertical direction and the value is 0 m/s
So
[tex]69 = 0 * t + \frac{1}{2} * 9.8 t^2[/tex]
=> [tex]t = \sqrt{\frac{2 * 69}{4.9} }[/tex]
=> [tex]t = 3.75 \ s[/tex]
Generally the distance which the robot have to hood the bucket in order to catch the turd is mathematically represented as
[tex]d = v_x * t[/tex]
=> [tex]d = 30 * 3.75[/tex]
=> [tex]d = 112.5 \ m[/tex]
What is the function of hammer and anvil in human ear
Answer:
Vibrations of the eardrum are in turn translated into oscillations of tiny bones (ossicles) found within the middle ear. The Hammer, Anvil, and Stirrup magnify the oscillations and relay this information to the chamber of the inner ear.
Answer:
The Hammer, Anvil, and Stirrup magnify the oscillations and relay this information to the chamber of the inner ear.
know the reasons why people have conflict
Answer:
just to have conflict
Explanation:
Answer:
·Some people find enjoyment in conflict. (Negative people and bullies)
·Sometimes the only thing that makes that person feel food is to throw people down.
·Conflict happens when two people disagree.
Explanation:
These are just some but there are many more :)
Hope this Helps
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The first step in a star formation is ______?
Which situation is most likely to lead to improving a scientific theory?
A. Repeating an experiment to verify results
B. Development of new technologies
C. Increased funding for research
D. Relaxing government restrictions
Answer:
A. Repeating an experiment to verify results
Explanation:
A scientific theory may be defined as the theory of science that is a thought out explanation of the observations done in the nature or that happens in the natural world. They are constructed using several scientific methods by observing many facts and hypothesis.
According to the question, repeating of an experiment a number of times and verifying its result may help in improving a scientific theory as if we get the similar result for each experiments, then it confirms the basis of the hypothesis or the facts that are observe in the nature and conclude a scientific theory.
Answer:
b
Explanation:
Q1) An action exerted on an object which may change the object's
state of rest or motion defines
a. acceleration.
b. force.
c. mass.
d. Velocity.
Answer: force...
Explanation:
A car has a velocity of 24 m/s. Two seconds later it reaches the bottom of the hill with a velocity of 45 m/s. What is the acceleration of the coaster?
Answer:
a = 10.5 m/s²
Explanation:
In order to find the acceleration of the car we will use the basic definition of the acceleration, that is the rate of change of velocity. So, the definition of the acceleration of the car will be:
a = (Vf - Vi)/t
where,
a = acceleration = ?
Vf = Final Velocity = 45 m/s
Vi = Initial Velocity = 24 m/s
t = time = 2 s
Therefore,
a = (45 m/s - 24 m/s)/2 s
a = 10.5 m/s²
A sled with no initial velocity accelerates at a rate of 3.2 m/s2 down a hill. How long does it take the sled to go 15 m to the bottom? *
How can mindfulness meditation help you with your well-being?
Answer:
It can really give you a new light and sense of your surroundings. With a well meditated mind, you can see things and feel different almost, but mostly same. But basically, with a meditated mind, you're more focused on what you're doing at the moment or what you're about to do.
Explanation:
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A 860g block of titanium metal has a volume of 200 cm3 and the density of 4.3g/cm^3.
What would be the density of the block of titanium metal if the volume of the block was 500 cm3 and the mass of the
block was 2150g?
Answer:
4.3 g/ cm^3
Explanation:
Mass / Volume = density . so 2150/500= 4.3 g/cm^3
Which of the following is a characteristic of a base?
A. pH greater than 7
B. pH between 4 and 13
C. pH between 4 and 9
D. pH less than 7
Answer:
A. pH greater than 7
Explanation:
Because a base has a pH scale of 8 to 14
A car initially traveling at 25 m/s speeds up to 60 m/s under a uniform acceleration of 5.0 m/s2 to avoid being hit by another car. How long does it take the car to speed up and get out of the way? Show your work.
Answer:
7 seconds
Explanation:
[tex]From\ the\ information\ provided, \ we\ know\ that:\\Initial\ velocity\ of\ the\ car=25\ m/s\\Final\ velocity\ of\ the\ car=60\ m/s\\\\Acceleration=5\ m/s^2\\[/tex][tex]As\ we\ know\ that\ , \\Acceleration=\frac{Change\ in\ velocity}{Change\ in\ time} \\a=\frac{v-u}{t} \\Hence,\\t=\frac{v-u}{a} \\Substituting\ u=25,v=60,a=5,\\t=\frac{60-25}{5}\\t=\frac{35}{5}\\t=7\ seconds[/tex]
Please help with this!
On the way down the ball's velocity is Positive 9.8.
Option A) is the correct answer.
What is velocity:?
This refers to the speed at which an object moves in a given direction. It unit is meters per secocond, m/s.
What is acceleration?
This is the rate of change of velocity with respect to time. The speed and direction of the accelerating object are also very important. It unit is meters per second square, m/s².
What is Gravity?
This is the force that pulls a body toward the center of the earth. This force causes objects to fall freely. This free-falling object has an acceleration of 9.8m/s downward the earth. This is called acceleration gravity.
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A permanent magnet picks up an iron nail, magnetizing the nail. How is this system different from an electromagnet?
Answer:the nail is magnetized by a permanent magnet instead of by a solenoid with an electric current running through it
Explanation:
The permanent magnet magnetizing the nail will differently function like electromagnet, by utilizing the electric current through the iron. Hence, option (B) is correct.
The given problem is based on the concept and fundamentals of magnetization. The term magnetizations means that the density of magnetic dipole moments induced in a magnetic material, when it is placed near a permanent magnet.
In the given problem, the magnetization of iron nail takes place by passing the current through the nail.The electric current utilize the electric charge which responds the electric field. When the current carrying nail is placed beside the permanent magnet, the dipole set up and it will create a polarity for which the nail will now itself behave as a magnet.Thus, we can conclude that the permanent magnet magnetizing the nail will differently function like electromagnet, by utilizing the electric current through the iron. Hence, option (B) is correct.
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Compute the electric charge on the surface which is the portion of the cone z = 3x2 + 3y2 in the first octant that lies between the planes z = 2 and z = 6. The charge density on the surface is given by σ(x, y, z) = xyz2 coulombs per square meter.
Answer:
9828 coulombs
Explanation:
z = [tex]\sqrt{3x^2 + 3y^2}[/tex]
Relation between the cartesian and polar coordinates
x = r cos ∅
y = r sin ∅
z = [tex]\sqrt{3x^2 + 3y^2}[/tex] = [tex]\sqrt{3r}[/tex]
next we calculate the surface charge density of the cone
б ( r, ∅ ) = xyz^2 = 3r^4 sin∅ cos∅
Charge given as
Q = ∫ б(r,∅ )ds
= ∫ б(r,∅ ) [tex]\sqrt{1 +( \frac{dz}{dx})^2 + (\frac{dz}{dx} )^2 } dA[/tex]
after integration
Q = ∫ б(r,∅ ) 2dA
Attached below is the remaining part of the solution
A truck moves 30 km West, and then 40 km North, and then travels in a straight path back to its starting
point. The distance travelled by the truck is km and its displacement is
km
Distance = (30+40+50) = 120 km
It's back where it started, so displacement = zero
The distance traveled by truck is equal to 70 km and its displacement is 50 km.
What are distance and displacement?The distance of an object can be described as the total path traveled by an object. It is a scalar quantity as it has only magnitude, not direction. The distance is always positive, it can never be zero.
The displacement can be described as the shortest distance between two points. The displacement is a vector quantity with both direction and magnitude. The displacement of an object can be positive, negative, or zero and can increase or decrease with time.
Given, a truck moves 30 km along AB in the West as shown in the attached figure below, and then 40 km North along BC.
The distance of the truck will be = AB + BC = 30 + 40 = 70Km
The displacement (AC) can be calculated by using Pythagoras' theorem:
AC² = AB² + BC²
AC² = (30)² + (40)²
AC² = 2500
AC = 50 Km
Therefore, the distance is 70 Km and the displacement of the truck is 50 Km.
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Which statement accurately describes planetesimals?
A. They are the origins of planets.
B. They formed from ice and rocks.
C. They were created during the big bang.
D. They contain 98% of matter in the solar system
Answer:
B
Explanation:
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6)Two forces are acting on 0.5-kg soccer ball.A is 230N and B is 250N.what is the acceleration of the soccer ball?
Answer:
B)
Explanation:
When a space shuttle was launched, the astronauts on board experienced an acceleration of 29.0 m/s2. If one of the astronauts had a mass of 60.0 kg, what net force in Newton’s did the astronaut experience?
a car is traveling at 30 metres per second it accelerates steadily for 5 seconds after which it is travelling at 50 metres per second calculate its acceleration
Answer:
its alot
Explanation:
what did taking measurements reveal about the velocity of the fireball? Was the fireball’s velocity constant or changing?
Answer:
The fireball slows down when moving upward. It speeds up when moving downward. So, its velocity is always changing.
Answer:
The fireball went in the air and slowed down. This is because, the gravity holds us down on earth and if not, we would be floating everywhere. So, the fireball slows down because the gravity is pulling it back down. As well as it's going down, it becomes faster. Just like when we jump, we come down pretty fast. So, when the gravity pulls you down and you go down it starts to pick up speed. Thats just how gravity works.
Explanation:
I put this in my own words.
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which term describes an object moving in two dimensions as it is acted on by gravity
Answer:
motion
Explanation:
Answer:
Projectile Motion
Explanation:
A p e x
Heading into a stop light, a car is traveling with a velocity of 44mph when the driver starts to app breaks. The car takes 15 seconds (or .0041hrs) to come to a complete stop. What is the car's acceleration/deceleration?
Answer:
the car slowed at a rate of 2.93 mph