Physlet Illustration: Work Done Pulling a Block Horizontally

 

 

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F = Newtons m = kg 
A block is pulled from rest by a constant force across a frictionless floor, as shown. The force on the box is represented by the black arrow. The velocity is given in m/s, and the distance grid is in meters. Adjust the mass (5 kg < m < 50 kg) and/or the pulling force (20 N< F < 200 N), and watch the graph of work done on the box vs. distance. How can you verify that the work done is calculated correctly?

Hints

  1. Choose any time to pause the animation.
  2. How far has the block moved in this time?
  3. How much work has been done on the block by this time?
  4. What is the block's speed at this time?
  5. What is its kinetic energy?
  6. What can you conclude about the relationship between work done on the block and its kinetic  energy?

Reference

See Walker, Sections 7-1 and 7-2

Illustration written by Steve Mellema and Chuck Niederriter