Question

A roller coaster car has 600,00 J of Kinetic energy as it approaches the station to stop. The roller coaster comes to a complete stop. How much work did the brakes do in stopping the car?

Answer 1

Answer:

Work Done by the Brakes = - 60000 J

Negative sign indicates the opposite direction of force and displacement.

Explanation:

Assuming that frictional effects are negligible, we can say that all the work done by the brakes is used to stop the car. We can apply law of conservation of energy to this situation as follows:

Work Done by the Brakes = Change in Kinetic Energy

Work Done by the Brakes = Final Kinetic Energy - Initial Kinetic Energy

Final Kinetic Energy of the roller coaster will be 0. Because, the roller coaster will stop finally and its velocity will become zero.

Work Done by the Brakes = 0 J - 60000 J

Work Done by the Brakes = - 60000 J

Negative sign indicates the opposite direction of force and displacement.