P1.1 Forces Year 7

What do the arrows show in a force diagram?

• the size and direction of the forces

• only size of the forces

• only the direction of the forces

• the biggest force

Answer explanation

The arrows show both the direction of a force (by the direction the arrow is pointing) and the size of a force (by the length of the arrow)

Which of the following are contact forces?

• Gravity

• Friction

• Air resisitance

• Magnetism

Answer explanation

A contact force only acts when something is touched.

Which of the following are non-contact forces?

• Gravity

• Air resistance

• Friction

• Magnetism

Answer explanation

Non-contact forces act even when not touching an object

What is used to measure forces?

• Newtons

• A newtonmeter

• A shoe

• gravitational field strength

Answer explanation

The equipment used to measure a force is called a Newtonmeter. It has a spring inside

When you apply a force to an object you can...

• compress it

• stretch it

• magnetise it

The amount that a spring or bungee cord can stretch is called the...

• elastic limit

• stretch force

• extension

• stretchiness

Answer explanation

The extension is the difference between the original length of the object, and the stretched length

Springs are special.

When you double the force on the spring, the extension should...

• triple

• not change

• not increase by as much

• double

Answer explanation

If the spring is observing Hooke's Law, each double of the force applied will also double the extension of the spring

Which of these can be a result of friction between two surfaces?

• heating up

• slows object down

• sound

Answer explanation

Friction is a contact force. It can cause the surfaces to heat up, you might heat sound, and also the objects move slower past each other if there is more friction

Which of these is a drag force?

• Air resistance

• Magnetism

• Gravity

• Water resistance

Answer explanation

Drag forces are experienced by objecting moving through a fluid (liquid or gas)

Which of the following will increase the air resistance on a sky-diver?

• Sticking out their arms and legs

• Wearing tight clothes

• Using a parachute

• Folding their arms