Forces and matter

What is the distortion of any material described as?

Elastic or inelastic

What does the distortion of any material require?

• It requires two forces

• Bending, stretching and compression all require two forces to be acting on the object

What is elastic distortion?

Elastic distortion means that a material will return to it’s original shape when the deforming force is removed

What is inelastic distortion?

Inelastic distortion means that a material will not return to it’s original shape after the deforming force is removed

What is the equation for the force exerted on a spring including the spring constant and extension?

Force exerted on a spring (N) = Spring constant (N/m) x extension (m)

F= k x X

What is the relationship between extension and force exerted in elastic distortion?

They are directly proportional to each other up to the elastic limit

What are the forces acting on an object floating in water?

• Weight is pushing the object down

• Upthrust is pushing the object up

• The force of the upthrust is equal to the weight of the fluid that is displaced

What is a fluid?

A liquid or a gas

What causes an object to float?

If it’s density is less than the fluid that it is in

What causes an object to sink?

If it’s density is more than the fluid that it is in

What happens to the pressure exerted by a fluid as it depth increases?

• The pressure increases

• This is because the further down you go in a liquid. the greater the weight of liquid there will be above

What does the total pressure acting on an object in a fluid depend on?

The pressure from the fluid and the atmospheric pressure

Why will water exert more pressure than cooking oil at the same height?

• A greater density means more weight will be acting downwards from above that depth

• The pressure exerted by water in greater than the oil because it has a higher density

What is atmospheric pressure?

It is the force exerted on an object due to the weight of the of the air above it in a column

How does atmospheric pressure change with height?

The further up you go, the less air there will be above you, so there will be less pressure