Physlet Illustration: The Work Done by Gravity on an Incline

 

 

 
m = Grams q = ° 
 
A block slides down a frictionless incline, as shown. The incline makes an angle q with the horizontal. The speed is given in m/s, the times shown are in seconds, and the distance grid is in meters. Adjust the mass (100 g < m < 500 g) and/or the angle (5° < q < 30°),  and watch the graph of work done on the block vs. distance it has travelled. 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. What force (or component of a force) does work on the block?

  4. How much work has this force done on the block by this time?

  5. What is the block's speed at this time?

  6. What is its kinetic energy?

  7. 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 Chuck Niederriter