How much work must be done by frictional forces in slowing a 1000-kg car from 26.1 m/s to rest?

Explanation:

Work done by the frictional force is 3.41x10^5 J

It is given that,

Mass of the car, m = 1000 kg

Initial velocity of car, u = 26.1 m/s

Finally, it comes to rest, v = 0

We have to find the work done by the frictional forces. Work done is equal to the change in kinetic energy as per work - energy theorem i.e.

W = −340605 J

or Hence, the correct option is (a).

another example of kinetic energy would be,

kinetic energy   >     moving energy

answer   >   letter choice (c),   a hammer falling off a table.

hope that !                                         : )