Question

The figure below shows a force distance graph for a car being towed on a level ground.

1. Calculate the total work done.
2. If the velocity just before reaching C is 0.6 m/s. Calculate the power developed by the engine at this point.

Answer 1

1. Calculate the total work done. 
   • Total work done = Area under graph 
     ( ½ x 4 x 600) + (600 x 4) + (½ x 2 x 600) + (2 x ½ x 600)
     1200 + 2400 + 600 + 600
     = 4800 J
2. If the velocity just before reaching C is 0.6 m/s. Calculate the power developed by the engine at this point. 
   • P = force x velocity
     = 0.6 m/s x 600
     = 360 W