Topic 3- Effects of Forces

Question 1

what can force change?

Answer 1

the shape of an object

Question 2

what does a squashing Force put an object under?

Answer 2

compression

Question 3

What is an example of a brittle material?

Answer 3

Glass

Question 4

what does brittle mean?

Answer 4

it does not change shape easily and breaks before stretching

Question 5

what are resilient materials?

Answer 5

materials that don’t break easily

Question 6

what are elastic materials?

Answer 6

materials that return to their original shape when the forces on them are removed.

Question 7

What are plastic materials

Answer 7

Plastic materials retain their new shape

Question 8

What does Hook’s law state?

Answer 8

hooks law states that the extension of a spring is proportional to the force used to stretch the spring.

Question 9

What does elastic limit mean?

Answer 9

the elastic limit is when up to a certain extension if the force is removed from the spring will return to its original length, the spring. is behind elastically.

Question 10

What happens if the elastic limit is exceeded?

Answer 10

the spring will be permanently stretched.

Question 11

What is the moment of a force’s formula?

Answer 11

moment = force x perpendicular distance from the pivot.

Question 12

If you were to calculate the moment exerted with the claw hammer if the person exerted a force of 80N and distance that equals 25CM

Answer 12

Moment = f X d
=80N X 25 CM
=80N X 0.25M
=20NM clockwise

Question 13

What is the centre of gravity?

Answer 13

The centre of gravity of a body is the point at which the weight of the body acts.

Question 14

what happens to the centre of gravity if it is suspended?

Answer 14

If suspended, a body will rest with its centre of gravity directly below the point of suspension.

Question 15

How do you find the centre of gravity on a card?

Answer 15

• pierce the card in at least 2 places
• suspend the card from one of these holes
• hang a plumbline from the point of suspension.
• using the plumbline as a reference draw a verticle line on the card
• repeat from either hole
• the centre of gravity is where the lines cross on the card.

Question 16

When is a body stable?

Answer 16

A body is stable as long as its centre of gravity remains vertically above its base, if not the body will topple.
to make it as stable as possible the body should have a wide base and a low centre of gravity.

Question 17

What is the principle of moments?

Answer 17

when an object is not turning: the total clockwise moment equals the Total anticlockwise moment.

Question 18

If a ruler is balanced, what is the formula for moments?

Answer 18

W^2 X d^2 = W^1 X W^1

Question 19

when a lorry is at the centre of a bridge, what will its weight be supported equally by?

Answer 19

it will be equally supported by the two columns

Question 20

How do you find the other force when finding forces on a bridge?

Answer 20

To find the other force you minus it from the force on the weight because force A and B add up to the force on the weight.