Legend

 F = Force

The pedal and gears for the bike are designed so that one foot can push down and create a torque.  This downward movement is further assisted by gravity. While the other foot lifts up, one pushes down.  This alternative movement creates torque that moves the gear and turns the wheel.

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 Before you start the Problems, be sure to have a pen/pencil and paper for working out the problems, and also a calculator.  If you want to use our java calculator:

1) A 75 kg mass hanging by a cord is held stationary midway between two supports, as shown.

 x 103 N

2) A uniform beam of 25 kg rests on supports P and Q.

what force is exerted by support Q on the beam?

 x 102 N

3) A mass suspended by a string is held 24o from the vertical by a force of 13.8 N as shown .  Find the mass.

 kg

4) The diagram shows a horizontal beam of negligible mass.  The wall exerts a 42.0 N horizontal force on the lever.  Find the weight of the load.

 N

5) Two cylindrical wheels of radii r1 = 30 cm and r2 = 50 cm are attached to each other on an axle that passes through the center of each.  Calculate the net torque on the wheel due to the two forces.

 mN
 RESULTS

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1) 2.1 X 103N
2) 1.6 X 102N
3) 0.57 kg
4) 16.1 N
5) 6.7 mN
 Formulas Circular Motion