two different people run a race the graphs track their distance vs. times during the race. Explain the difference between the two runners motions. use words like speed and acceleration.

Which of the following statements is true? a. most heat energy is easily recovered and used for useful actions. b. friction causes molecules to vibrate more slowly. burning air and gasoline in an c. engine changes chemical energy into mechanical energy. it is impossible to d. change mechanical energy into mechanical energy.