WA3
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Thomas Edison State College *
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230
Subject
English
Date
Apr 3, 2024
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docx
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2
Uploaded by DeanPheasantPerson1053
Written Assignment 3
Answer all
of the following questions. Do not send in a partially completed assignment. Answer each question as completely as possible, but do not merely copy answers from your reading materials. If you cite a reference in the text, explain the meaning of the citation.
1.
Define the term impulse
.
Impulse is equal to force multiplied by the amount of time that object is subjected to that force.
2.
Using the principle of momentum conservation, explain what happens when a moving billiard ball collides with a stationary ball (cue ball hitting the eight ball).
The cue ball is in motion and transfers its momentum to the eight ball. This causes the eight ball into motion and the cue ball stops.
3.
Explain the difference between energy and power and how they are related to work. Give examples of each.
A 1000 kilogram car is lifted 1 meter.
a.
What is the potential energy with respect to the floor?
Potential Energy (initial): U = mgh = (1000 kg)(9.8 m/s²)(1 m) = 9800 J
b.
If the car is lifted 2 meters high, what is the new value of potential energy with respect to the floor?
Potential Energy (final): U = (1000 kg)(9.8 m/s²)(2 m) = 19600 J
c.
Explain the following: Potential energy of an object varies linearly with position (height).
The formula U = mgh shows that potential energy is directly proportional to height (h). As the height increases, potential energy increases linearly. This is because the gravitational force acting on the object is constant, and the work done (and therefore potential energy gained) is directly proportional to the height lifted.
4.
As you catch a fast-moving fastball, why is it wise to move your hand in the direction of the ball's motion? Explain in terms of work and energy.
You can lessen the force of the ball by extending the time of the interaction between your hand
and the ball by moving your hand back as you catch the ball. The work portion of this is bringing the ball to a rest as the energy transfers to your hand.
5.
If a sprinter running at a speed of 10 meters per second could convert his/her kinetic energy into upward motion, how high could he/she jump?
h=v
2
/2g
v=10 m/v=10m/s
g=9.8 m/s2g=9.8m/s2
h=(10 m/s)
2 /2×9.8 m/
s2
h=100/19.6 m
h≈5.1 metersh≈5.1meters
Copyright © 2017 by Thomas Edison State University. All rights reserved.
6.
What various forms of energy are present as you shoot a bow and arrow?
Drawing the bowstring back creates potential energy and when the string the energy is converted to kinetic energy and it transfers this energy to the arrow 7.
Answer the following questions:
a.
If you push a lawn mower across a yard in 10 seconds, how does the work done compare with pushing it across the same yard in 20 seconds? Explain why. This is the same amount of work just spread out over twice the time. The force required to push it across in 20 seconds would require half the force as pushing it across in ten seconds.
b.
How does the power for 10 seconds compare to the power for 20 seconds?
The power for 10 seconds would be double the power for 20 seconds.
8.
How many kilometers per liter will a car obtain if its engine is 25 percent efficient and it
encounters an average force of 1000 Newtons? Assume the energy content of gasoline is 40,000,000 joules per liter (J/L).
10 km/L
40,000,000 J/L / 1000 N = 40,000 m/L = 40 km/L x .25 = 10 km/L
Copyright © 2017 by Thomas Edison State University. All rights reserved.
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