Levers and moments

Question 1

Describe a pivot

Answer 1

It is a point about which a force can cause an object to turn
eg the centre of a seesaw

Question 2

Identify the 3 parts of a lever

Answer 2

Effort load and pivot

Question 3

Explain the load on a lever

Answer 3

The force of the object on the lever acting downwards

Question 4

A fulcrum is another name for?

Answer 4

A pivot

Question 5

Why is a lever often called a machine

Answer 5

Because it can help us do a job more easily

Question 6

Finish the sentence the longer the lever the…….

Answer 6

greater the turning force about the pivot

Question 7

Explain the advantage of using a longer spanner as a lever?

Answer 7

A longer spanner acts as a longer lever.
This gives more of a turning force about the pivot
Which means that less effort is needed to move the load.

Question 8

What is a moment?

Answer 8

It is the turning effect of a force

Question 9

Describe what happens when a force acts on something which has a pivot

Answer 9

a turning effect is produced - called a moment
eg someone sits on the end of a seesaw

Question 10

What is the formula used to calculate a moment

Answer 10

Moment = force x perpendicular distance

Question 11

What is the unit of measurement of a moment

Answer 11

Nm Newton metres

Question 12

How do you calculate a moment?

Answer 12

Multiply the distance of the lever in metres by the force in Newtons

Be careful if they give a distance in cm you must turn them into metres

Question 13

What is balanced moment

Answer 13

When the clockwise and anticlockwise moments are equal

Question 14

The clockwise moment is 10Nm and the anticlockwise moment is 8NM which direction will it turn

Answer 14

Clockwise because the moment is bigger in that direction

Question 15

A meter ruler has a pivot in the middle, if a weight of 6N is hung on the end what will the moment be?

Answer 15

6N x 0.5m = 3Nm

Question 16

A meter ruler has a pivot in the middle, two weights are hung either side of the pivot, you know the weights and their distance from the pivot how do you find out if the ruler is balanced

Answer 16

Multiply the weight of each by the distance from the pivot.
If the answers are the same it is balanced

Question 17

The test has a picture of a balanced ruler with a pencil through it and two weights hanging on it. It shows you the weight of one and the distance from the pivot of both of them. How can you calculate the 2nd weight?

Answer 17

1. Multiply the weight you know by it’s distance from the pivot to get the moment
   If it is balanced the moments will be equal
2. Divide the moment by its distance from the pivot to get the 2nd weight