1. calculate the kinetic energy of a car with a mass of 500 kg traveling at a velocity of 10 m/s north. a. 2,500 j b. 50,000 j c. 100 j d. 25,000 j 2. a rock has a mass of 25 kg. the acceleration due to gravity is 10 m/s^2 and the height of the height of the rock is 42 m. find the potential energy of the rock. a. 1,050 j b. 5,250 j c. 220,500 j d. 10,500 j 3. thermal equilibrium is reached when a. objects have enough kinetic energy for them to be at terminal velocity b. the sound vibrations reach a high pitch c. two objects in contract with each other are the same temperature d. the net force on an object is zero