Complete question is;
Shoveling snow can be extremely taxing since the arms have such a low efficiency in this activity. Suppose a person shoveling a sidewalk metabolizes food at the rate of 800 W. (The efficiency of a person shoveling is 3%.)
(a) What is her useful power output? (b) How long will it take her to lift 3000 kg of snow 1.20 m? (This could be the amount of heavy snow on 20 m of footpath.) (c) How much waste heat transfer in kilojoules will she generate in the process?
Answer:
A) P_out = 24 W
B) t = 1470 s
C) Q = 1140.72 KJ
Explanation:
We are given;
Input Power; P_in = 800 W
Efficiency; η = 3% = 0.03
A) Formula for efficiency is;
η = P_out/P_in
Making P_out the subject, we have;
P_out = η•P_in
P_out = 0.03 × 800
P_out = 24 W
B) We know that;
Power = work done/time taken
Thus;
P_out = mgh/t
We are given;
m = 3000 kg
h = 1.20 m
Thus, time is;
t = (3000 × 9.8 × 1.2)/24
t = 1470 s
C) amount of heat wasted is calculated from;
Q = (P_in - P_out)t
Q = (800 - 24) × 1470
Q = 1,140,720 J
Q = 1140.72 KJ
mathematical expression between wave number and frequency
Three identical very dense masses of 3800 kg each are placed on the x axis. One mass is at x1 = -
230 cm, one is at the origin, and one is at
x2 = 350 cm. Take the gravitational constant to be G = 6.67×10−11N⋅m2
/kg2
a) calculate the gravitational attraction of the object located at x1 on the object sitting at the
origin. (magnitude and direction. Take the direction from the origin to the right as
POSITIVE)
b) Calculate the gravitational attraction of the object located at X2 on the object at the origin.
(magnitude and direction)
c) Calculate the total gravitational attraction of the objects located at x1 and the object sitting at
x2 on the mass located at the origin. (magnitude and direction).
Answer:C
Explanation:
I think its c im pretty sure
BRAINLIEST PLEASE HELP ASAP DO NOT ANSWER UNLESS YOU KNOW AND DON'T GIVE ME A LINK OR I WILL REPORT YOU
1. Explain what type of lever is a baseball bat and why the bat is that type of lever in relation to the input force, output force, and fulcrum.
2. Explain for which class of lever is the output force always greater than the input force.
3. Explain for which class of lever is the output force always less than the input force.
4. Use the law of conservation of energy to explain why in a second class lever the distance over which the input force is applied is always greater than the distance over which the output force is applied.
5. A lever has an IMA of 4. If the length of the length of the input arm is 1.0 meter, what is the length of the output arm.
Answer:
In a third class lever, the effort is located between the load and the fulcrum. ... If the fulcrum is closer to the effort, then the load will move a greater distance. A pair of tweezers, swinging a baseball bat or using your arm to lift something are examples of third class levers.
Explanation:
In what way would a digital thermometer be preferable to those from a liquid-based thermometer?
what the answer for this question ?
Answer:
Explanation:
It is better to say “It is correct.” The word THIS is a demonstrative pronoun. The word THIS should be used to point out or to indicate the things. The word CORRECT is an abstract noun therefore it can not be pointed out this is why it is better to say IT IS CORRECT.
suppose that you want to build a machine to perform simple tasks. why must you understand all about forces to complete your mission?
Answer:
CAUSE YPU WANT TO
Explanation:
An open organ pipe emits E (330 Hz ) when the temperature is 26 ∘C. The speed of sound in air is v≈(331+0.60T)m/s, where T is the temperature in ∘C. Determine the length of the pipe.
Answer:
0.525 m
Explanation:
From the question,
In an open pipe,
v = λf................... Equation 1
Where v = speed of sound in the pipe, f = frequency, λ = wave length.
But,
λ = 2l................ Equation 2
Where l = length of the pipe
Substitute equation 2 into equation 1
v = 2lf.............. Equation 3
make l the subject of the equation
l = v/2f............. Equation 4
Given:
v ≈ (331+0.60T) m/s at T = 26°C
v ≈ (331+0.60×26) ≈ 346.6 m/s
f = 330 Hz.
Substitute these values into equation 4
l = 346.6/(2×330)
l = 346.6/660
l = 0.525 m
Hence the length of the pipe is 0.525 m
Three capacitors, C1 = 2 μF, C2 = 4 μF, C3 = 4 μF, are connected in series Determine the capacitance of a single capacitor that will have the same effect as the combination.
Answer:
1 μF
Explanation:
To obtain the answer to the question, all we need to do is to calculate the equivalent capacitance of the capacitors. This can be obtained as illustrated below.
From the question given above, the following data were obtained:
Capacitor 1 (C₁) = 2 μF
Capacitor 2 (C₂) = 4 μF
Capacitor 3 (C₃) = 4 μF
Equivalent capacitance (Cₑq) =?
Cₑq = 1/C₁ + 1/C₂ + 1/C₃
Cₑq = 1/2 + 1/4 + 1/4
Cₑq = (2 + 1 + 1)/4
Cₑq = 4/4
Cₑq = 1 μF
Thus, the answer to the question is 1 μF
As a woman walks, her entire weight is momentarily placed on one heel of her high-heeled shoes. Calculate the pressure exerted on the floor by the heel if it has an area of 1.45 cm2 and the woman's mass is 53.0 kg. Express the force in N/m2 and lb/in2. (In the early days of commercial flight, women were not allowed to wear high-heeled shoes because aircraft floors were too thin to resist such large pressures.)
Answer:
The correct answer is "517.7 lb/in²".
Explanation:
The given values are:
Woman's mass,
m = 53 kg
Area,
A = 1.45 cm²
= [tex]1.45\times 10^{-4}[/tex] m²
Now,
The weight of woman will be:
⇒ [tex]W=mg[/tex]
On substituting the values, we get
⇒ [tex]=53\times 9.8[/tex]
⇒ [tex]=519.4 \ N[/tex]
Pressure will be:
⇒ [tex]P=\frac{W}{A}[/tex]
⇒ [tex]=\frac{519.4}{1.45\times 10^{-4}}[/tex]
⇒ [tex]=3.57\times 10^6 \ N/m^2[/tex]
or,
⇒ [tex]=3.57\times 10^6 \ Pa[/tex]
As we know,
⇒ 1 pound per sq. inch = 6895 Pascal's
hence,
⇒ [tex]P=\frac{3.57\times 10^6}{6895}[/tex]
⇒ [tex]=517.7 \ lb/in^2[/tex]
Which of the following is NOT true about Potential Energy?
An object's position affects its potential energy
O Objects with more mass have more potential energy
Potential energy is Stored energy
Potential energy only occurs when an object is in motion
Answer:
Potential energy only occurs when an object is in motion.
Explanation:
Energy can be defined as the ability (capacity) to do work. The two (2) main types of energy are;
a. Kinetic energy (K.E): it is an energy possessed by an object or body due to its motion.
Mathematically, kinetic energy is given by the formula;
[tex] K.E = \frac{1}{2}MV^{2}[/tex]
Where;
K.E represents kinetic energy measured in Joules.
M represents mass measured in kilograms.
V represents velocity measured in metres per seconds square.
b. Potential energy (P.E): it is an energy possessed by an object or body due to its position above the earth.
Mathematically, potential energy is given by the formula;
[tex] P.E = mgh[/tex]
Where,
P.E represents potential energy measured in Joules.
m represents the mass of an object.
g represents acceleration due to gravity measured in meters per seconds square.
h represents the height measured in meters.
Additionally, the mechanical energy of a physical object or body is the sum of the potential energy and kinetic energy possessed by the object or body.
Mathematically, it is given by the formula;
Mechanical energy = P.E + K.E
A 1.0-kg object moving 9.0 m/s collides with a 2.0-kg object moving 6.0 m/s in a direction that is perpendicular to the initial direction of motion of the 1.0-kg object. The two masses remain together after the collision, and this composite object then collides with and sticks to a 3.0-kg object. After these collisions, the final composite (6.0-kg) object remains at rest. What was the speed of the 3.0-kg object before the collisions
Answer:
v₃ = - (3 i ^ + 4 j ^) m / s
v₃ = 5 m / s, θ = 233º
Explanation:
This is a momentum problem. Let us form a system formed by the three objects so that the forces during the collisions have been internal and the moment is conserved.
Let's start working with the first two objects. As each object moves in a different direction let's work with the components in an xy coordinate system
X axis
initial instant. Before the shock
p₀ₓ = m₁ v₁₀ + 0
final instant. After the crash
p_{fx} = (m1 + m2) vₓ
the moment is preserved
p₀ₓ = p_{fx}
m₁ v₀₁ = (m₁ + m₂) vₓ
vₓ = [tex]\frac{m_1}{m_1+m_2} \ v_{o1}[/tex]
Y axis
initial instant
p_{oy} = 0 + m₂ v₀₂
final moment
p_{fy} = (m₁ + m₂) v_y
the moment is preserved
p_{oy} = p_{fy}
m₂ v₀₂ = (m₁ + m₂) v_y
v_y = [tex]\frac{m_2}{m_1 +m_2 } \ v_{o2}[/tex]
We already have the speed of the set of these two cars, now let's work on this set and vehicle 3
X axis
initial instant
p₀ₓ = (m₁ + m₂) vₓ + m₃ v₃ₓ
final instant
p_{fx} = 0
p₀ₓ = p_{fx}
(m₁ + m₂) vₓ + m₃ v₃ₓ = 0
v₃ₓ = [tex]- \frac{m_1+m_2 }{m_3} \ v_x[/tex]
Y Axis
initial instant
p_{oy} = (m₁ + m₂) v_y + m₃ v_{3y}
final moment
p_{fy} = 0
p_{oy} = p_{fy}
(m₁ + m₂) v_y + m₃ v_{3y} = 0
v_{3y} = [tex]- \frac{m_1+m_2}{m_3} \ v_y[/tex]
now we substitute the values of the speeds
v₃ₓ = [tex]- \frac{m_1+m_2}{m_3} \ \frac{m_1}{m_1+m_2} \ v_{o1}[/tex]
v₃ₓ = [tex]- \frac{m_1}{m_3} \ v_{o1}[/tex]
v_{3y} = [tex]- \frac{m_1+m_2}{m_3} \ \frac{m_2}{m_1+m_2} \ v_{o2}[/tex]
v_{3y} = [tex]- \frac{m_2}{m_3} \ v_{o2}[/tex]
let's calculate
v₃ₓ = - ⅓ 9
v₃ₓ = - 3 m / s
v_{3y} = - ⅔ 6
v_{3y} = - 4 m / s
therefore the speed of vehicle 3 is
v₃ = - (3 i ^ + 4 j ^) m / s
It can also be given in the form of modulus and angles using the Pythagorean theorem
v₃ = [tex]\sqrt{v_{3x}^2 + v_{3y}^2}[/tex]
v₃ = [tex]\sqrt{3^2+4^2}[/tex]
v₃ = 5 m / s
let's use trigonometry for the angle
tan θ' = [tex]\frac{v_{3y}}{v_{3x}}[/tex]
θ' = tan⁻¹ (\frac{v_{3y}}{v_{3x}})
θ' = tan⁻¹ (4/3)
θ' = 53º
That the two speeds are negative so this angle is in the third quadrant, measured from the positive side of the x axis
θ = 180 + θ'
θ = 180 +53
θ = 233º
Charge of uniform density (40 pC/m2) is distributed on a spherical surface (radius = 1.0 cm), and a second concentric spherical surface (radius = 3.0 cm) carries a uniform charge density of 60 pC/m2. What is the magnitude of the electric field at a point 2.0 cm from the center of the two surfaces?
Answer:
E = K Q / R^2 by Gauss' Law where Q is the charge enclosed by the surface of revolution and R is the distance from the enclosed charge
Since Q = d 4 pi r^2 where d is the charge density and r the radius of the inner sphere
E = K / R^2 * (4 d pi r^2) = 4 K pi d (r / R)^2 = 4 K pi d * 1/4
E = 9 * 10E9 * 3.14 * 40 * 10E-12 = 1.13 N / C
Which statement accurately describes viscosity
Answer:
D.
Explanation:
Viscosity is a measure of a fluid resistance to flow. It describes the internal friction of a moving fluid. A fluid with large viscosity resists motion because its molecules makeup gives it a lot of internal friction.
A particle with a charge of 34.0 $\mu C$ moves with a speed of 65.8 m/s in the positive $x$ direction. The magnetic field in this region of space has a component of 0.545 T in the positive $y$ direction, and a component of 0.828 T in the positive $z$ direction. What is the magnitude of the magnetic force on the particle
Answer:
0.00221 N
Explanation:
Given that,
The charge on the particle, [tex]q=34\mu C[/tex]
The speed of the particle, v = 65.8 m/s (+x direction)
Magnetic field, B = 0.545 T (in +y direction) and 0.828 T in the positive z direction.
The magnetic force is given by the formula as follows :
[tex]F=q(v\times B)[/tex]
Substitute all the values,
[tex]F=34\times 10^{-6}\times (65.8i\times (0.545j+0.828 k))\\\\=34\times 10^{-6}\times (65.8i\times 0.545j +65.8i\times 0.828 k)\\\\=34\times 10^{-6}\times(35.86k +(-54.48j))\\\\=34\times 10^{-6}\times \sqrt{35.86^2+54.48^2} \\\\=0.00221\ N[/tex]
So, the magnitude of the magnetic force on the particle is equal to 0.00221 N.
Wind turbines continue to generate energy even when there isn't any wind.
O True
O False
How is a credit card reader related to magnetism?
a 12v battery delivers a 3.6 a current to an electric motor. How much power was delivered to the current?
Answer:
P = 43.2 W
Explanation:
Known:
Voltage = 12 v = 12 kgm^2s^-3A^-
Current = 3.6 A
Unknown:
Power =?
Strategy:
We need an equation the relates voltage, power, and current. According to Watt's Law, the power in a circuit is a product of voltage and current.
This defines the relationship between power, voltage, and current.
The mathematical expression of watt's law is P = IV where p is the power delivered or generated by a given source, I is current, and V is the voltage.
Solution:
P = 3.6 A * (12 kgm^2s^-3A^-1)
P = (43.2 kgm^2s^-3A)/A [ I have moved the A^-1 into the denominator as A so that we can see that we have the same term in the numerator and denominator.
P = 43.2 kgm^2s^-3
P = 43.2 W
Physics question 28 plz help me
Answer:
a. I = 30 A
b. E = 1080000 J = 1080 KJ
c. ΔT = 12.86°C
d. Cost = $ 4.32
Explanation:
a.
The current in the coil is given by Ohm's Law:
[tex]V = IR\\I = \frac{V}{R}[/tex]
where,
I = current = ?
V = Voltage = 120 V
R = Resistance = 4 Ω
Therefore,
[tex]I = \frac{120\ V}{4 \Omega}\\[/tex]
I = 30 A
b.
The energy can be calculated as:
[tex]E = VIt\\E = (120\ V)(30\ A)(5\ min)(\frac{60\ s}{1\ min})\\[/tex]
E = 1080000 J = 1080 KJ
c.
For the increase in the temperature of water:
[tex]E = mC\Delta T\\[/tex]
where,
m = mass of water = 20 kg
C = specific heat of water = 4.2 KJ/kg.°C
Therefore,
[tex]1080\ KJ = (20\ kg)(4.2\ KJ/kg.^oC)\Delta T[/tex]
ΔT = 12.86°C
d.
First, we will calculate the total energy consumed:
[tex]E=(Power)(Time)\\E=VI(Time)\\E = (120\ V)(30\ A)(0.5\ h/d)(30\ d)\\E = 54000\ Wh\\E = 54 KWh[/tex]
Now, for the cost:
[tex]Cost = (Unit\ Cost)(Energy)\\Cost = (\$ 0.08\KWh)(54\ KWh)[/tex]
Cost = $ 4.32
The speed of a train is reduced uniformly from to while travelling a distance of 90 m. a. Compute the deceleration b. How much further will the train travel before coming to rest, provided the acceleration remains constant?
Answer:
290 m.a.
Is answer
I don't know properly
But I hope you like it
Sorry
need help urgent please
A wave pulse travels along a stretched string at a speed of 100 cm/s. What will be the speed in cm/s if the string's tension is quadrupled, the length halved and its mass is doubled
Answer:
The new velocity of the string is 100 centimeters per second (1 meter per second).
Explanation:
The speed of a wave through a string ([tex]v[/tex]), in meters per second, is defined by the following formula:
[tex]v = \sqrt{\frac{T\cdot L}{m} }[/tex] (1)
Where:
[tex]T[/tex] - Tension, in newtons.
[tex]L[/tex] - Length of the string, in meters.
[tex]m[/tex] - Mass of the string, in kilograms.
The expression for initial and final speeds of the wave are:
Initial speed
[tex]v_{o} = \sqrt{\frac{T_{o}\cdot L_{o}}{m_{o}} }[/tex] (2)
Final speed
[tex]v = \sqrt{\frac{(4\cdot T_{o})\cdot (0.5\cdot L_{o})}{2\cdot m_{o}} }[/tex]
[tex]v = \sqrt{\frac{T_{o}\cdot L_{o}}{m_{o}} }[/tex] (3)
By (2), we conclude that:
[tex]v =v_{o}[/tex]
If we know that [tex]v_{o} = 1\,\frac{m}{s}[/tex], then the new speed of the wave in the string is [tex]v = 1\,\frac{m}{s}[/tex].
5) Unlike the five big mass extinctions in the geological record, the current wave of extinctions is
caused by
A.
Human activity
В. Volcanism
C.
Sea level changes
D.
Changes in ocean chemistry
E Asteroid impact
Answer:
B.Volcanism
Explanation:
Cause every time the current wave moves is causes and eruption
Unlike the five big mass extinctions in the geological record, the current wave of extinctions is caused by the Volcanism. Thus, the correct option is B.
What is the cause of Mass extinction?A mass extinction event is also known as biotic crisis. It is a widespread and rapid decrease in the biodiversity on the Earth which could be due to various reasons. Such an extinction event is identified by a sharp change or decrease in the diversity and abundance of multicellular organisms in an area.
Past mass extinctions on this planet were caused due to extreme temperature changes, rise or fall in the sea levels and catastrophic events, one-off events like a huge volcano erupting or an asteroid hitting the Earth. The current wave of extinctions is caused by volcanism.
Therefore, the correct option is B.
Learn more about Mass extinctions here:
https://brainly.com/question/11872946
#SPJ6
True or false? Charges flow from high voltage to low voltage
difference between centrifugal and semi-centrifugal clutches
Answer:
Semi-centrifugal clutches are used in high powered race cars, to reduce the driver effort. Working is just like semi-centrifugal clutch.
The clutch action is purely under centrifugal force.
At low engine rpm the centrifugal force is low, so there is slip, as engine rpm increases, so does the centrifugal force.
If a base runner passes a forward runner who is not out, the passing runner is _________.
A. safe
B. out
C. awarded a base
D. faster than the first runner
Answer:
the answer might be the first one A. safe
Answer: B. Out
Explanation: i took the quiz.
To decrease the angle between the anterior surface of the foot and anterior surface of the lower leg is described as:
Answer:
dorsiflexion
Explanation:
To decrease the angle between the anterior surface of the foot and anterior surface of the lower leg is described as: dorsiflexion
Answer:
dorsiflexion
Explanation:
Hope this helps
A string with a length of 0.75 m is fixed at both ends. (a) What is the longest possible wavelength for the traveling waves that can interfere to form a standing wave on this string? (b) If waves travel with a speed of 130 m/s on this string, what is the frequency associated with this longest wavelength?
Answer:
a) Longest wavelength is: [tex]\lambda_{1}=2*0.75=1.5\: m[/tex]
b) The frequency associated with this longest wavelength is: [tex]f=86.7\: Hz[/tex]
Explanation:
a)
The wavelength equation of a standing wave is given by:
[tex]\lambda_{n}=\frac{2}{n}L[/tex]
Where:
L is the length of the stringn is a natural numberWe use n=1 to find the longest possible wavelength, so we will have:
[tex]\lambda_{1}=2L[/tex]
[tex]\lambda_{1}=2*0.75=1.5\: m[/tex]
b)
The speed of the wave is given by:
[tex]v=f\lambda[/tex]
So we just need to find the f (frequency).
[tex]f=\frac{v}{\lambda}[/tex]
[tex]f=\frac{130}{1.5}[/tex]
[tex]f=86.7\: Hz[/tex]
I hope it helps you!
How does Newton's first law affect human motions answer
Tritium (hydrogen-3) undergoes radioactive decay to produce helium-3. Which
particle needs to be added to this equation to show that the total numbers of
neutrons and protons are not changed by the reaction?
H He + ?
O A. He
O B. He
O c., e
O D.,
An electron particle needs to be added to this equation to show that the total number of neutrons and protons is not changed by the reaction.
Explain the tritium decay?Tritium has nearly the same chemical characteristics as regular hydrogen. It produces helium-3 by releasing a beta particle and decaying with a half-life of 12 years.
Tritium breaks down into helium by producing a beta particle. The discharge of radiation during this decay process raises questions regarding tritium's and other radioactive compounds' safety.
The radiation produced by tritium decay is in the form of low-energy beta particles.
The chemical equation representation during the tritium decay is;
₁H³→₂He³+₋₁e⁰
The particle needs to be added to this equation to show that the total number of neutrons and protons are not changed by the reaction will be an electron.
Hence option D is correct.
To learn more about the tritium decay refer to the link;
https://brainly.com/question/17256358
How far did the object travel from time = 0 to time =15 s 120 m. 180 m 90 m 45 m
Answer:Position is an object’s location in relation to a reference point.
Yes. As in the movie theater example, an object can be one unit positive from the reference point and a different object can be one unit negative from the reference point. Both objects are one unit away (the same distance), but they occupy different locations in space because they are in different directions.
Distance is the total amount an object has traveled, while displacement is the shortest distance between the object’s starting and finishing point.
Distance does not have direction. Objects can be one unit away from a point in every direction. However, displacement does have a direction. Displacement is defined as a specific distance in a specific direction.
Explanation: hope it helped