# Worksheet: Kinetic Energy

In this worksheet, we will practice calculating the kinetic energy of an object moving relative to an observer given its mass and velocity.

**Q7: **

A spring has a mass of 10.0 g, uniformly distributed along its length. The left end of the spring is fixed. The right end of the spring is moving in the -direction at 0.125 m/s and the right end of the spring is at the equilibrium position . What is the kinetic energy of the spring?

- A J
- B J
- C J
- D J
- E J

**Q10: **

If wind is blowing horizontally toward a car at an angle of 30 degrees from the direction of travel, the kinetic energy of the car will . If the wind is blowing at a car at 135 degrees from the direction of travel, the kinetic energy of the car will .

- Adecrease, increase
- Bincrease, decrease
- Cdecrease, decrease
- Dremain the same, increase
- Eincrease, increase

**Q13: **

The Chicxulub crater in Yucatan, one of the largest existing impact craters on Earth, was created by an asteroid that has been modeled as impacting the Earth traveling at 22 km/s, dissipating J of energy. What is the minimum mass of the asteroid necessary to have done this?

- A kg
- B kg
- C kg
- D kg
- E kg

**Q16: **

A man with a mass of 75.0 kg is in a subway train car that is moving along some tracks at 15.00 m/s. The man walks at a speed of 1.500 m/s, first in the same direction as the car’s motion, and then in the opposite direction to the car’s motion.

What is the man’s kinetic energy relative to the car when he walks in the same direction as the car’s motion?

What is the man’s kinetic energy relative to the car when he walks in the opposite direction to the car’s motion?

What is the man’s kinetic energy relative to the tracks when he walks in the same direction as the car’s motion?

What is the man’s kinetic energy relative to the tracks when he walks in the opposite direction to the car’s motion?