A mountain climber drops a grapefruit from the top of the Alps (4809 m). If all the kinetic energy that it gains while falling changes into thermal energy, what would be its temperature change when it hit the ground? (specific heat capacity for grapefruit is 3800 J/kg·°C)

Idon’t quite understand this problem

Suppose you have a box. which of these is not necessarily a true statement regarding the relationship between the force applied to the box, the work done on the box, and the distance the box is moved? a. if the box is not moved, no force is being applied to the box. b. if no force is applied to the box, no work is done on the box. c. if work is done on the box, then a force is applied to the box. d. if work is done on the box, then the box is moved a distance.

Polly is pushing a box across the floor with a force of 30 n. the force of gravity is –8 n, and the normal force is 8 n. which value could describe the force of friction if polly could not move the box?