Pulley exercises

1) Describe how pulleys made loading and sailing huge cargo vessels possible.

2) Explain how pulleys were used during the industrial revolution.

3) Consider a set of pulleys linked by a belt. Which one comment is false?
a) Force can be multiplied.
b) Speed can be increased.
c) All pulleys must rotate in the same direction.
d) Speed can be decreased.

4) A pulley system can:
a) increase force and speed at the same time;
b) decrease speed while increasing force;
c) decrease force and speed at the same time;
d) change the direction of motion.

5) Look at the pulley system on the right. Pulley A and B are the same size while pulley C is a third the size of B .

Does pulley C rotate faster or slower than pulley A?
Describe the speed of pulley B as compared to pulley A?
If pulley A rotates clockwise describe the rotation of pulleys A and B.
Pulley A exerts a force measured at 10 units. What is the force exerted by pulley C and B?

6) Consider the gears on a bicycle.It represents a pulley system.

a)What gear, A or B, should the rider select when taking off from a stationary start? Explain.

b)When moving along the highway what gear should the rider select in order to increase the speed of the bike? Explain.

bicycle gears represent a pulley system.

c) Look at eh gear selection of the rider pictured on the right. This selection is suitable when:
a) taking off after red lights;
b) accelerating down the highway;
c) going up a hill;
d) stationary.

7) Consider the pulley system on the right. Pulley A is connected to a steam engine. It is connected by belts to pulley B.

a) Does pulley A rotate clockwise or anticlockwise?
b) Will pulley B rotate clockwise or anticlockwise?
b) If pulley A rotates at 20 revolutions per minute (RPM) how fast will pulley B rotate?
c) If pulley A generates a force of 100 units what is the force exerted by pulley B?
8) Consider the pulley system on the right. How far will the 200kg load rise if 2m of rope is pulled though the pulleys?

9) a) What mass is needed to just lift the 100kg load using the pulley system shown on the right?

b) What is the mechanical advantage of this machine?

10) a) What is the maximum load that can be lifted by the pulley system on the right?

b) For every metre the load is lifted what length of rope must be pulled through the pulleys?
11) a) What is the maximum load that can be lifted by the pulley system on the right?

b) For every metre the load is lifted what length of rope must be pulled through the pulleys?
12) What is the maximum load that can be lifted by the pulley shown on the right?

13) Consider the pulley system on the crane shown on the right.
How many pulleys are present?


What is the mechanical advantage of this pulley system?