Name
Period Date
1.
For his birthday, Ben Celebrating purchases a long spring which he decides to mount vertically on the ground outside of his bedroom window. When Ben places a box of mass 20. kg on the spring it compresses 0.98 m . a.
Draw a force diagram of the box b.
Calculate the spring constant of the when it rests on the spring. spring.
In a playful mood, Ben’s sister Styll drops Ben’s
5.0 kg physics notes out of his window. Luckily, after falling 15 m , Ben’s notes hit the long, vertical spring compressing it an unknown distance as in the diagram.
AP Physics c.
How much is the spring compressed by his notes?
(Hint: If you get 2.7 m as your answer, you forgot that the spring compresses!)
15 m x
AP Physics

Energy: Worksheet 2 page2
18 m
3.2 m
2.
Tarzan, who weighs 688 N , swings from a cliff at the end of a convenient vine that is
18 m long as in the diagram above. From the top of the cliff to the bottom of the swing, he descends by 3.2 m . The vine will break if the force on it exceeds 950 N . a.
Where in Tarzan’s swing is the vine most likely to break? Explain. b.
How fast will Tarzan be moving at the bottom of his swing? c.
Does the vine break? Prove your answer. Draw a force diagram of Tarzan at the bottom of his swing to begin.

Energy: Worksheet 2 page3
3. A pendulum consists of a 2 .
0 kg stone swinging on a 4 .
0 m string. The stone has a speed of 8 .
0 m s
when it passes its lowest point.
a. How far above the lowest point is the stone when it is at a 50 .

angle to the vertical? b. What is its speed when the string is at a 50 .

angle to the vertical?
L 50 .

? c. What is the largest angle with the vertical that the string will reach during its motion? d. Using the lowest point of the string as the zero of gravitational potential energy, what is the total mechanical energy of the system?

Energy: Worksheet 2 page4
4. A box of mass m is pulled from rest by the little engine. The box moves a distance d of across a horizontal surface when it will be moving at speed v . The coefficient of kinetic friction between the box and the ground is
 k
. Answer (b)
– (e) in terms of m , d , v ,
 k
and fundamental constants. a. Draw a force diagram of the box. b. What is the force of kinetic friction between the box and the ground? c. Using energy considerations, determine the force of tension in the rope as the box is being pulled. d. What is the acceleration of the box? e. Using Newton’s Laws, determine the force of tension in the rope as the box is being pulled. Show your work! f. Calculate the answers to (b) – (e) if the mass of the box is 200 .
kg , the box is moving at 2 .
7 m s
after being pulled a distance of 2 .
5 m , and the coefficient of kinetic friction between the box and the ground is
 k

0 .
20 .