Problem 4. A box of mass m = 2.0 kg is at rest at point B on a rough inclined plane with length s = &8.0 m (distance between A and B), and which makes an angle of 30° with the horizontal. The velocity of the box at point A is 2.5 m/s. (a) What is the work done by gravity between the top (B) and the bottom (A) of inclined plane? (b) Find the work done by the net force on the box. (c) Find the increase in thermal energy in the box-incline system as a result of friction.

An asteroid is moving along a straight line. A force acts along the displacement of the asteroid and slows it down. The asteroid has a mass of 3.5× 104 kg, and the force causes its speed to change from 7100 to 5400m/s. (a) What is the work done by the force? (b) If the asteroid slows down over a distance of 1.8× 106 m determine the magnitude of the force. (a) Work = Choose your answer for sign in part (a) here                                                             Type your answer for part (a) here Choose your answer for units in part (a) here                                                             (b) F = Type your answer for part (b) here Choose your answer for units in part (b) here

The force required to compress a non-standard spring varies as the spring is compressed, as shown by the plot of force vs displacement. Distances are x1 = 10, x2 = 25 cm, x3 = 55 cm, and x4=75cm, and the forces are F1 = 110 N and F2 = -60N. Calculate the work done in Joules, on the spring as it is compressed from origin to point x4.

A 4.8 kg box has an acceleration of 1.8 m/s? when it is pulled by a horizontal force across a surface with 4, = 0.50. Find the work done over a distance of 22 cm by the following forces. (Enter your answers in joules.) (a) the horizontal force (b) the frictional force (c) the net work (d) what is the change in kinetic energy of the box?

1. A jeep with mass of 2000 kg is going 18 m/s at the bottom of a hill that is 50.0m high. When it reaches the top, it is travelling at 10m/s. (a) what is the total work done by all forces (the jeep engine, the mud, gravity, etc) as it ascends the hill? (b) What is the minimum work required by engine of the jeep if only the engine and gravity are doing work (if there is na friction, forces from mud, etc)?

A person pulls a 26 kg package with a cord, on an icy path at constant velocity, on level ground.  The cord makes a 20.0 degree angle with the ground.  If the coefficient of friction between the package and the ground is 0.16, and the package moves for 120 m, (a) find the work done by the tension in the cord, and (b) the work done by the friction.

The force on a particle is directed along an x axis and given by F = F0(x/x0 - 1) where x is in meters and F is in Newtons. If F0 = 1.6 N and x0 = 4.6 m, find the work done by the force in moving the particle from x = 0 to x = 2x0 m.