Question

A 0.54 kg air hockey puck is initially at rest. What will it's kinetic energy energy be after a net force of 0.56 N acts on it for a distance of 0.84m?

Answer 1

Answer:

Kf = 470 mJ

Explanation:

• According the work-energy theorem, the change in the kinetic energy of one object, is equal to the net work done on it.
• Since the puck is initially at rest, the change is kinetic energy is just the final kinetic energy of the puck.
• Assuming that the net force is horizontal, and causes a horizontal displacement also, we can find the net work on the puck as follows:

       $W_{net} = F_{net} * \Delta X = 0.56 N * 0.84 m = 0.47 J = 470 mJ (1)$

• As we have already said, (1) is equal to the final kinetic energy of the puck:
• ⇒ Kf = 470 mJ  (2)