One model of tennis ball launcher has advertised that it is capable of imparting 15,000 J of kinetic energy to a 0.5 kg ball initially at rest. A
student carefully measures the compression of the spring to be 0.10 m-
What is the value of the spring constant for the tennis ball launcher
according to the data provided?

The answer for the first question is: 3,000,000 N/m

The answer for the second question is: If the question was, "Which of the following is the best example of kinetic energy being transformed into potential energy?" then the answer is winding the spring on a toy car

Explanation:

For the first question: I have no explanation, I just got it right on my test so I thought i'd help you out.

For the second question: (i'll try to explain the best I can).

Kinetic energy = energy in motion

Potential energy = stored energy

so when winding the spring of a car you are using energy in motion (kinetic energy) to create stored energy (potential energy) that will be used to move the car. So it goes something like:

kinetic energy > potential energy > kinetic energy

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards