20. Which of the following statement/s is/are always true about the work energy theorem? The total mechanical energy (E), the sum of potential energy (U) and kinetic energy (K), is equal to zero. II If only conservative forces are applied on an object, such as gravity and friction, the total mechanical energy is conserved. III If there are non-conservative forces applied on an object, the total mechanical energy is not conserved. a. I only b. I and II only c. I, II, and III d. None of the aboveSHOW YOUR COMPLETE SOLUTION AND WRITE YOUR SOLUTION ON A PAPERFor Problems 21-23: A car with mass 800 kg moves in a straight line on a frictionless horizontal surface. At point A, its speed is 15 Infs while at Point B, its speed increased to 26 m/s. Point A to point B is 39 meters apart. 21. How much is the work done by the car? a. 180.4] b. 180.4 k] c. 48.4] d. 48.4 k] 22. Use the work-energy theorem to find the force acting on the car, with the assumption that the force is constant and acts in the direction of the car. a. 4.6 N b. 4,620 N c. 1.2 N d. 1,200 N 23. What is the acceleration of the car? a. 5.8 m/s2 b. 1.6 m/s2 c. 11.6 mfs2 d. 3.2 m/s2