5.4 Forces (moments, levers and gears)

Question 1

What is a moment?

Answer 1

The turning effect of a force about a pivot

Question 2

What can the direction of the moment be?

Answer 2

clockwise or anticlockwise

Question 3

What is the equation for moment?

Answer 3

moment = force x perpendicular distance from pivot
m = f x s

Question 4

What is s?

Answer 4

distance

Question 5

The further the force is applied from the pivot, what increases?

Answer 5

the moment exerted by it

Question 6

What are the principles of moments?

Answer 6

• When two or more forces can combine to produce no overall turning effect, this is called the principle of moments
• When an object’s anticlockwise moment is equal to the clockwise moment, the object is in equilibrium and won’t turn

Question 7

If an object is in equilibrium, what can be said about the moments acting on the object?

Answer 7

The clockwise moments are equal to the anticlockwise moments

Question 8

What distance measurement is used when calculating a moment?

Answer 8

The perpendicular distance from the pivot to the line of action of the force

Question 9

If the anticlockwise moment is bigger, where will the seesaw turn?

Answer 9

anti-clockwise

Question 10

What do levers do?

Answer 10

It increases the distance from the pivot to where the force is applied

Question 11

What are levers?

Answer 11

force multipliers and increase the size of the force acting on the object, hence less force is required for the same moment

Question 12

What do gears do?

Answer 12

they transmit rotational effects

Question 13

What happens when a small gear turns a big gear?

Answer 13

It gives a low speed but a high turning effect

Question 14

What happens when a large gear turns a small gear?

Answer 14

It gives a high speed but a low turning effect

Question 15

If one gear turns, what will the other gear do?

Answer 15

turn the opposite direction

Question 16

what are gears referred to as?

Answer 16

they are referred to as circular discs with teen which interlock one another

Question 17

What three parts make up a lever system?

Answer 17

1. Load
2. Effort
3. Pivot

Question 18

How can a lever be used as a force multiplier?

Answer 18

If the distance between the effort and pivot is greater than the distance between the pivot and load, the force applied on the load is greater than the effort force. this is since the moment on both the effort and load must be the same

Question 19

Give an example of when a lever may be used to multiply a force

Answer 19

A wrench, which has a long handle so that the force applied by the user is multiplied

Question 20

What determines the moment of a gear wheel?

Answer 20

the size of the wheel

Question 21

Describe the moment and speed of a larger gear being driven by a smaller gear

Answer 21

The larger wheel will rotate more slowly but will also produce a larger moment