29.A 50 kg box is pulled across a surface by a force of 100 N. A constant force of friction of 25 N acts against the object. Find the object's acceleration. Energy , work and power 30.What are the two main components of mechanical energy?Explain . 31. If a mouse and an elephant both run with the same kinetic energy, can you say which is running faster? Explain in terms of the equation for KE. 32. A 35 kg chair is lifted 5 m off the ground. What is its potential energy? Show work. 33.Calculate the kinetic energy of a 3.1 kg toy cart that moves at 4.8 m/s. (b) Calculate the kinetic energy of the same cart at twice the speed. Show work. 34. A boulder is raised above the ground so that its potential energy relative to the ground is 20,000 J. It is then dropped. What is its kinetic energy just before it hits the ground? Show work. 35.Another bowling ball is suspended from the ceiling on a rope. You decide to start it swinging by pulling back on it so that it is raised 0.45 meters higher than it was to start. You let it swing: how fast is it moving at the bottom of its swing? How fast is it going at the top of its swing? Show work. Momentum 36. A rifle recoils while firing a bullet. Explain why the speed of the rifle's recoil is small compared to the speed of the bullet. 37. An egg dropped on concrete usually breaks while one dropped on grass usually doesn't break. Explain why this is true, your answer should include discussion about time and force. 38. The following questions refer to the motion of a sports car.Show work. a. Calculate the momentum of a 1000 kg sports car traveling at 30 m/s. b. Determine the impulse needed to increase the car's speed from 30 m/s to 35 m/s. c.In a sad turn of events, the same sports car, formerly traveling at 35 m/s, plows into a rock wall and comes to rest in 0.25 seconds. Determine the size of the force the rock wall exerts on the car. d. How does the size of the force the rock wall exerts on the car compare to the force the car exerts on the rock wall? Briefly explain. Which of Newton's laws of motion applies to your answer? 39. On an icy road, a 5000 kg truck rear-ends a 1200 kg car that had been traveling at 13 m/s, causing the truck to slow from 14 m/s to 12 m/s and the car to speed up. Find the final velocity of the car.Show work