Advanced Physics Quiz: Mechanical Energy, Power, Efficiency, Circular Motion, and Torque

A rollercoaster cart reaches the top of a 45-meter hill at 5 m/s. Ignoring friction, what is its speed at the bottom of the hill?

• 30.1 m/s
• 25.3 m/s
• 20.5 m/s
• 15.7 m/s

A machine requires 1500 Joules of input energy to lift a 50 kg mass 2 meters. What is the efficiency of this machine?

• 65%
• 78%
• 82%
• 91%

If a satellite orbits Earth at twice the radius of another satellite, how does its orbital period compare to the closer satellite?

• √2 times longer
• 2 times longer
• 2√2 times longer
• 4 times longer

A 2000 W motor lifts a 100 kg mass. What is the maximum speed at which it can lift this mass?

• 1.5 m/s
• 2.0 m/s
• 2.5 m/s
• 3.0 m/s

Why does a spinning figure skater speed up when pulling their arms in?

• Mass increases
• Angular momentum decreases
• Moment of inertia decreases
• Rotational energy increases

A force of 50 N is applied at a 30° angle to a wrench that is 0.3 m long. What is the resulting torque?

• 7.5 N·m
• 15.0 N·m
• 13.0 N·m
• 11.5 N·m

In a frictionless system, what happens to mechanical energy during circular motion?

• Converts entirely to kinetic energy
• Converts entirely to potential energy
• Remains constant but shifts between forms
• Gradually decreases

A wheel rotating at 240 rpm is slowed to 60 rpm in 10 seconds. What is its angular acceleration?

• -1.88 rad/s²
• -2.51 rad/s²
• -3.14 rad/s²
• -4.19 rad/s²

Which combination of changes would increase the centripetal force needed for circular motion?

• Decrease mass, increase radius
• Increase mass, decrease speed
• Increase mass, increase speed
• Decrease mass, decrease radius

If a machine's efficiency is 80% and its output power is 400 W, what is its input power?

• 320 W
• 450 W
• 500 W
• 550 W