3. A crate, having a mass of 45 kg, is pulled steadily upwards by two ropes through a height of 12 m. Each rope has a mass of 0.75 kg/m. Draw the force vs distance graph and determine the work done in pulling the crate 12 m upwards. 4. A variable force (as shown in the diagram) is applied to a 3.9 kg mass which is moving at a velocity of 3.0 m/s [E] along a horizontal frictionless surface. Find the velocity of the mass after the displacement of 9.0 m [E]. Force (N [E]) 2.0 6.0 9.0 Displacement (m [E])1. A girl pulls a cart of mass 15 kg along a horizontal surface by means of a rope which makes an angle of 3? with the horizontal. The force applied to the rope is 64 N In an eastward direction and the coefcient of kinetic friction is 0.35. The cart is pulled through a horizontal distance of 120 m. Find: a. The work done by the girl b. The work done by friction c. The net work done 2. The hammer of a pile driver has a mass of 320 kg and it falls through a distance of 6.5 m before hitting the top of the pile. After the blow, the pile is send 1? cm into the ground. What is the average force on the pile