5. A loaded cart has a total mass of 400 kg. If a 500 N force acting at an angle of 40o to the ground is applied, how much work is done in moving the cart 20 m? 6. The rotor of a motor has a moment of inertia 12 kg-m2 . What constant unbalanced torque is required to increase its speed from 120 rpm to 420 rpm in 6 s? 7. A block of wood floats in water with 0.646 of its volume submerged. In oil it has 0.918 of its volume submerged. Find the density of the wood and the oil