Forces

Question 1

What is a force?

Answer 1

A push or a pull

Question 2

What unit are forces measured in?

Answer 2

Newton

Question 3

What piece of equipment measured forces?

Answer 3

Newton-meter

Question 4

How can forces affect the movement of an object?

Answer 4

(i) Change it’s speed (faster/slower)
(ii) Stop it moving
(iii) Change it’s direction
(iv) Change it’s shape

Question 5

How can forces be represented on a diagram?

Answer 5

Forces can be represented by arrows in a certain direction.

The size of the force must be labelled.

Question 6

What is a contact force?

Answer 6

A contact force is a push or a pull on one object by another object that is touching it.

Question 7

What is a non-contact force?

Answer 7

A force that pushes or pulls on an object without touching it is called a non-contact force

Question 8

Give an example of a non-contact force?

Answer 8

• Gravitational force
• Magnetic force
• forces due to static electricity

Question 9

Do forces act alone or in pairs?

Answer 9

Forces always act in pairs. These pairs are called interaction pairs.

Question 10

What is weight?

Answer 10

Theweightof an object is defined as theforceof gravity on the object.

Question 11

What is drag force/air resistance?

Answer 11

It is the force that acts on objects as move/fall through the air.

Question 12

How does drag/air resistance affect the speed of a moving object?

Answer 12

It slows it down.

Question 13

What type of shape can decrease the effect of air resistance.

Answer 13

A stream-lined shape

Question 14

What type of force is thrust?

Answer 14

This can be any driving force, it may be a push or pull, but it could be an engine which forces an object forward.

Question 15

What type of force is lift?

Answer 15

This is the force required to raise an object through a fluid. e.g. the force pulling an airplane upwards is lift.

Question 16

What is friction?

Answer 16

It is a force that acts on objects when they are in contact with a surface, such as the ground. It slows objects down.

Question 17

How can the force of friction be reduced?

Answer 17

Lubrication e.g. adding oil to the engine of a car.

Question 18

What is gravity?

Answer 18

This pulling force affects every object on Earth. It is a force which pulls everything to the centre of the earth.

Question 19

What is upthrust?

Answer 19

This is an upward force which acts in water, it acts on a object against gravity, and is why certain objects float.

Question 20

What is tension?

Answer 20

Tension is a pulling force as tension can only pull an object. e.g. there is a tension force on the lead when walking a dog.

Question 21

If the forces on an object are BALANCED (or if there are no forces acting on it), what happens to the object?

Answer 21

• a stationary object stays still.

- a moving object continues to move at the same speed and in the same direction.

Question 22

When are forces UNBALANCED?

Answer 22

When two forces acting on an object are not equal in size, we say that they are unbalanced forces.

Question 23

When forces are unbalanced it can cause an object to…

Answer 23

• Move

- Change it’s speed

Question 24

What is the difference between weight and mass

Answer 24

• The weight of an object is the force of gravity on the object. Weight is measured in Newtons.
• Mass is a measurement of how much of something there is. Mass is measured in grams and kilograms.

Question 25

What does Hooke’s Law state?

Answer 25

Hooke’s Law states: “If you double the force applied to a spring then the extension of the spring will double”.

Question 26

What is elastic limit

Answer 26

This is the point of a spring/elastic beyond which it will deform and not return to it’s original shape.