4. An object with mass m = 4.00 kg is originally placed at the edge of the cliff. On the left end of the object, the spring with spring constant k = 212 N/m is attached. Then the object is compressed by 0.802 m, and let go. First, it travels a horizontal surface of distance d = 1.50 m with the friction coefficient a = 0.105. Then it reaches the end of the cliff so that it starts falling down the cliff of height h = 5.20 m, aka projectile motion. Assume the spring and the object get separated as soon as the object is let go. (a) What is the initial energy of the object when it was let go off the spring ? (b) What is the work done by friction as it moves along the horizontal surface ? (c) What is the energy of the object when it is about to fall (at the end of the cliff) ? (d) What is the velocity of the object at the end of the cliff ? (e) What is the final velocity of the object when it hits the bottom of the cliff ?5. Consider an object with mass m = 5.00 kg attached to a spring with spring constant k = 395 N/m. The object is compressed by 0.415 m and let go. Assume that the object sticks with the spring the whole time after it is let go. This is a so-called simple harmonic motion. Assume that there exists air resistance of 25.1 N that constantly acts on the object as the object oscillates. The direction of the air resistance is opposite to the direction of motion. (a) What is the amplitude of this spring ? (b) What is the initial amount of energy the object has when it is let go ? (c) What is the amount of work done by the air resistance when the object reaches the equilibrium position for the first time ? (d) What is the total energy of the object when it reaches the equilibrium position for the first time ? (e) What is the total energy of the object when it reaches the equilibrium position for the second time