question_answer

  (a) A battery lights a bulb. Describe the energy  changes involved in the process.            (b) Calculate the amount of work needed to  top a car of 500 kg, moving at a speed of 36 km per hour.                  

Answer:

   (a) When a battery lights a bulb, its chemical energy changes into light and heat energy.           (b) m = 500 kg, v = 0, and u = 36 km/h Work done = Change in kinetic energy               It is negative, because work is done to stop the car.