Question

A toy car has a kinetic energy of 8 J. What is its kinetic energy after a frictional force of 0.5 N has acted on it for 6 m?

Answer 1

Final kinetic energy,
`KE_f=5\ J`

Step-by-step explanation:

It is given that,

Kinetic energy of toy car,
`KE_i = 8\ J`

Frictional force, F = 0.5 N

Distance, d = 6 m

We need to find the kinetic energy after this frictional force has acted on it. We know that frictional force is an opposing force. The work done by the toy car is given by :

`W=F* d`

`W=-0.5\ N* 6\ m`

W = -3 J

We know that the work done is equal to the change in kinetic energy. Let
`KE_f` is the final kinetic energy.

`W=KE_f-KE_i`

`-3=KE_f-8`

`KE_f=5\ J`

So, the final kinetic energy is the toy car is 5 J. Hence, this is the required solution.