# Physics revision notes

- Created by: Bethany Cunningham
- Created on: 20-01-12 20:42

MUST CONVERT UNITS TO THE RIGHT ONES

Motion:

Acceleration = gradient= vertical

horizontal

Distance = Area underneath graph

Know the difference between speed and velocity

Speed describes the time taken for an object to cover a certain distance.

Speed = distance (m)

(m/s) time (s)

Velocity describes speed in a given direction.

Know how to calculate acceleration when given the formula

Acceleration is the change in velocity over time.

Acceleration = final velocity - initial velocity

(m/s2) time taken

If an object starts from stationary then the velocity is zero.

How to calculate stopping distances and what affect it?

Thinking distance and braking distance = stopping distance.

The difference between mass and weight

Mass is how much matter something is made of.

Weight is a force due to gravity.

How to calculate weight?

Weight is a force due to gravity. So its units are in Newtons.

It is mass x gravitational field strength

(kg) (10 kg m/s2)

[Just times by 10)

What terminal velocity is?

No resultant force equals to terminal velocity

*When an object falls the two forces that affect it are gravity and air resistance

At first the gravity force is greater than the air resistance so the object accelerates in a downwards direction. As the object accelerates downwards (at 10 m/s2 on Earth), its velocity increases. As the velocity increases the air resistance force increases in the opposite direction. Eventually the air resistance force and the force of gravity balance each other out and so there is zero resultant force on the object. The object has now reached its TERMINAL VELOCITY.

Work, energy and momentum:

How to calculate work done and GPE?

Work done is all about the energy transferred and so the unit is Joules.

The things that affect work done are the weight an object and the distance.

The formula for work done is:

Work done = weight x distance

(J) (kg) (M)

The higher something goes, the more gravitational potential energy.

Gpe = mass x gravitational field strength x height

What terminal velocity is?

No resultant force equals to terminal velocity

*When an object falls the two forces that affect it are gravity and air resistance

At first the gravity force is greater than the air resistance so the object accelerates in a downwards direction. As the object accelerates downwards (at 10 m/s2 on Earth), its velocity increases. As the velocity increases the air resistance force increases in the opposite direction. Eventually the air resistance force and the force of gravity balance each other out and so there is zero resultant force on the object. The object has now reached its TERMINAL VELOCITY.

Work, energy and momentum:

How to calculate work done and GPE?

Work done is all about the energy transferred and so the unit is Joules.

The things that affect work done…

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