eloquent logic - equilibrium

Legend

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.

問題

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 24^o from the vertical by a force of 13.8 N as shown . Find the mass.

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.

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.

RESULTS

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