Pietro Maximoff

per second and has a mass of 84 kilograms.
A: What is his momentum when he’s traveling at that speed?
B: What is his kinetic energy when he’s traveling at that speed?
C: How much force is required if he starts at rest and it takes him half a second to reach
that speed?
2 (10 points): A solid sphere and a hollow sphere roll down a one-meter ramp inclined at 45°.
Both have a mass of 0.75 kilograms and a radius of 7 centimeters. The solid sphere has a moment
of inertia of 2𝑀𝑅
2
5
while the hollow sphere has a moment of inertia of 2𝑀𝑅
2
3
. Both spheres start
from rest, travel the same distance, and roll simultaneously. Which one reaches the bottom of the
ramp first? Explain your reasoning.
3 (15points): A sixteen-ton weight is suspended seven feet in the air. (16 tons = 14,515
kilograms and 7 feet = 2.1336 meters)
A: What is the weight’s potential energy?
B: How much work was done to raise the weight?
C: If the rope breaks, how fast will the weight be going when it hits the ground?
4 (20 points): Saturn has a mass of 5.7 × 1027 kilograms and an equatorial radius of 60,268
kilometers. Its rotational period is 10 hours and 42 minutes.
A: What is Saturn’s rotational velocity?
B: What is the linear velocity of a point on the surface of Saturn?
C: Assuming Saturn is a solid, rigid sphere (𝐼 =
2𝑀𝑅
2
5
), what is its angular momentum?
D: What is its rotational kinetic energy?
5 (20 points): A typical regulation curling stone has a mass of 1.860 kilograms and can be no
bigger than 914.4 millimeters in diameter. The player who delivers the stone is known as the
skip. In a perfect throw, the stone will leave the skip’s hand at about 2 meters per second and
slide 28.35 meters across the ice before coming to a complete stop.
A: Typically, the stone will rotate about two and a half times before it stops sliding.
What is its angular velocity? (Assume its angular acceleration is zero).
B: How much friction acted on the stone? Is this kinetic friction or static friction?