Physlet Illustration: Accelerating a Train

 

 

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F = Newtons m1= kg  m2= kg m3= kg 
 
A train, consisting of three blocks connected by rods, is pulled by a constant force (shown as a black arrow) across a frictionless floor. The velocity is given in m/s, and the times shown are in seconds. Adjust the masses (20 kg < m < 100 kg) and/or the pulling force (0  N < F < 100 N), and measure the train's acceleration. Does the train obey Newton's Second Law?  What are the tensions in each of the connecting rods?

Hints

  1. Measure acceleration by finding the change in velocity over a specific time interval.
  2. How do the accelerations of the individual blocks compare?
  3. Draw a free-diagram for each block.
  4. Equate the sum the forces on each block to its acceleration.

Reference

See Walker, Section 6-2

Illustration written by Steve Mellema and Chuck Niederriter