Section 2: Numerical Problems. Show your work. (10 point each) N1. A 10 Kg box is pushed across a distance of 2 meters by applying a force of 20 N. How much work is done to accomplish this? N2. A metal ball of mass 5 kg is dropped from a tower of height 30 m. What is its total mechanical energy when it just reaches the ground. N3. Two particles of mass m1 = 4 kg and m2 = 8 kg undergo a one-dimensional head-on collision as shown in the figure below. Their initial velocities along x are v1; = 15 m/s and v2; = - 6.0 m/s. The two particles stick together after the collision (a completely inelastic collision). (Assume to the right as the positive direction). Find the magnitude and direction of velocity after the collision. m 1 m2 N4. A diver stands at rest at the end of a 20 kg diving board. Find the total torque due to gravity on the diving board. Assume the mass of the board is uniformly distributed. (Assume that the mass of the diver is 50.0 kg and the length of the board is 2.0 m.) N5. Calculate the density of a wooden block of mass 25 kg and volume 0. 5 m3 N6. An artificial moon subtends an angle of about 20 to us on Earth, 2.5 X 104 km away. Estimate the radius of the moon