# Calculate Combined Kinetic Energy of Boy and Wagon

## What is the combined kinetic energy of a boy and a toy wagon moving at a constant speed?

Calculate the combined kinetic energy of a boy and a toy wagon that total to a mass of 60 kg and are moving at a constant speed of 2.0 m/s.

a. 1600 J

b. 2400 J

c. 3200 J

d. 4000 J

## Answer:

The combined kinetic energy of the boy and the wagon, which total to a mass of 60 kg and are moving at a constant speed of 2.0 m/s, is calculated to be 240 J. The correct answer choice is (b).

**Explanation:** To calculate the combined kinetic energy of the boy and the wagon, we use the kinetic energy formula KE = 0.5 × m × v^2, where m is the mass and v is the velocity. The total mass of the boy and the wagon is 40 kg + 20 kg = 60 kg. Plugging the values into the formula gives us KE = 0.5 × 60 kg × (2.0 m/s)^2 = 120 J × 2 = 240 J.

Therefore, the combined kinetic energy of the boy and the wagon moving at a constant speed of 2.0 m/s is 240 J.