A force multiplier is a simple machine that easily moves a large load. A small force on the effort
end of the lever puts a large force on the load. Force is multiplied.
Force multipliers and speed multipliers
Machines can make work easier by reducing the amount of force necessary to move an object or
increasing the speed of an object relative to the force applied to it.
Force multipliers are devices that reduce the amount of force necessary to move an object.
Force multipliers are useful for lifting heavy objects or doing other things that require large
amounts of force. Some examples of force multipliers are inclined planes and most levers.
Speed multipliers are devices that increase the speed of, or distance travelled by, an object.
Although more force than usual is required to move the object in these cases, the extra force is
changed into more kinetic energy. Speed multipliers are useful when an object needs to move a
further distance or at a higher speed. Some examples are wheels and axles and third class levers.
Identify which of the following statements is true.
Effort is the force needed to move an object.
Force and work effectively mean the same thing.
The load is the energy needed to move an object.
Effort and load are measured in joules.
A simple formula for work is:
work = effort force x distance.
If the work required is 24 joules, and the effort force is 8
newtons, calculate the distance required to do the job.
16 metres
3 metres
32 metres
192 metres
This diagram shows an inclined plane (ramp). If a box is pushed up a
frictionless ramp, identify which of the following statements would be true.
If the ramp was longer but the height remained the same, more effort would
be needed.
The work in raising the box depends on the method.
Pushing the box requires more work than lifting it.
The heavier the box, the more effort is required.
The ancient Egyptians used ramps to build the pyramids. Identify which of
these statements about working with ramps is true.
The work is less, but the effort remains the same.
The work remains the same, but the effort is more.
The work is less and the effort is less.
The work remains the same, but the effort is less.
Mechanical advantage can be calculated using the formula:
mechanical advantage = load/effort.
Identify which of the following has the greatest mechanical advantage.
A 1000 N load lifted with a 500 N effort.
A 600 N load lifted with a 100 N effort.
A 200 N load lifted with a 400 N effort.
A 500 N load lifted with a 500 N effort.
The zipper is a twentieth-century invention. Identify what a zipper uses.
2 wedges
1 wedge
4 wedges
3 wedges
From a mechanical point of view, identify which of the following is the odd one
out.
A knife
A screw
Incisor teeth
An axe
Consider this diagram and identify which of the following statements is true.
The steeper the ramp, the less the spring balances will read.
All four spring balances should read the same.
The spring balances on the ramps will read the same.
The work in raising the block or trolley by 10 cm remains the same.
Identify what this diagram is an example of.
Class 2 levers
Class 4 levers
Class 1 levers
Class 3 levers
Identify what this diagram is an example of.
Class 2 levers
Class 4 levers
Class 1 levers
Class 3 levers
Class 1 and 2 order levers obey a rule called the Principle of Levers:
effort x effort arm length distance = load x load arm length distance
The weight of a load is increased and placed at the same load arm length
(distance) from the fulcrum. Identify which of the following changes could not
balance this new load.
Increasing the effort and increasing the effort arm length.
Keeping the effort the same, but increasing the effort arm length.
Keeping the effort and effort arm length (distance) the same.
Increasing the effort, but keeping the effort arm length the same.
The load on both of the depicted levers is the same. Identify what needs to
happen to balance the loads.
One effort needs to be about five times the other.
The effort on both levers must be the same.
One effort needs to be about triple the other.
One effort needs to be about double the other.
This diagram shows a class 3 lever. Identify which of the following statements
is not true about this kind of lever.
The load moves faster than the effort does.
Compared to the effort, the load moves a short distance at low speed.
The effort is greater than the load.
As the load moves through a greater distance, the force on it is small.
This diagram shows a wheel and axle. Identify which of the following
statements is not true.
A point on the axle moves at a faster speed than a point on the rim of the
wheel.
The axle and rim of the wheel turn the same angle in the same amount of
time.
If the axle moves through 90°, then the rim of the wheel also moves through
90°.
The further out the rim of the wheel is, the faster its speed of turn.
The steering wheel of a car and a ceiling fan are both examples of
wheels. Identify which of the following is true.
Both are speed multipliers.
Both are force multipliers.
The steering wheel is a force multiplier while the ceiling fan is a speed
multiplier.
The steering wheel is a speed multiplier while the ceiling fan is a force
multiplier.
This diagram shows some types of gears. Identify the letter representing the
rack and pinion gear.
C
B
D
A
This diagram shows a double pulley system. The load has weight (W) in
newtons, and needs to be raised through a distance (D) in
metres. Identify which is true about the effort.
The force needed is 2W moved through a distance 2D.
The force needed is 2W moved through a distance 0.5D.
The force needed is 0.5W moved through a distance 2D.
The force needed is 0.5W moved through a distance 0.5D.
Identify which of the gear wheels on the right of each gear train will spin
anticlockwise.
B and C
A and B
A and C
Only A
Identify what this diagram is an example of.
Class 4 levers
Class 2 levers
Class 1 levers
Class 3 levers
This diagram shows an example of a class 2 lever. Explain what happens as the
load moves closer to the fulcrum.
Less effort is required to lift it.
The same effort is required to lift it.
A greater effort is required to lift it.
The work done in lifting it alters.