7. An object has 25 J of kinetic energy and 15 J of potential energy. Work is done on the

object leaving it with 25 J of kinetic energy and 30 J of potential energy. How much work

is done on the object?

15 J

Explanation:

Total energy before work will be from the sum of both kinetic and potential energy hence 25+15=40 J

Similarly, the total energy after work will be given by the sum of kinetic and potential energy. This will be 25+30=55 J

The difference of the two gives the amount of work done hence 55-40=15 J

Therefore, work done which is as a result of energy increase in the system is equivalent to 15 J