Question

The graph shows the kinetic energy of both a school bus and a pickup truck as they move at various speeds. Under which of the following conditions can the pickup truck have more kinetic energy than the school bus?
The pickup truck is moving at 1 m/s and the school bus is moving at 2 m/s. The pickup truck is moving at 4 m/s and the school bus is moving at 2 m/s.
The pickup truck is moving at 2 m/s and the school bus is moving at 3 m/s.
The pickup truck is moving at 4 m/s and the school bus is moving at 3 m/s.

Answer 1

The correct answer is B. The pickup truck is moving at 4 m/s and the school bus is moving at 2 m/s.

Explanation:

The kinetic energy is related to how fast a body moves (speed), as well as, the amount of matter in the object (mass). Due to this, even if the bus and the truck move at the same speed they do not have the same kinetic energy. Indeed, the graph shows in general the kinetic energy is higher for the school bus.

However, this does not occur if the truck moves at 4 m/s and the bus moves at 2m/s because, at this speed, the kinetic energy of the truck is 30 kilojoules, while the kinetic energy of the bus is around 15 kilojoules, which is lower. According to this, the correct answer is B.