Physics - Topic 1 (Key words)

Scalar

Scalar

Quantity with magnitude only

Vector

Quantity with magnitude and direction

Distance

How far apart 2 objects are

Displacement

How far apart 2 objects are in a straight line

Speed

How quickly an object travels

Velocity

How quickly an objects travels in a particular direction

Terminal velocity

The object moving at a steady speed in a constant direction

Instantaneous speed

Speed at a particular point in time

Acceleration

Change in velocity within a given time

Uniform acceleration

Constant acceleration

Force

Push, pull or twist

Resultant force

Single overall force used to represent ALL the forces acting on an object

Contact forces

Forces that occur when 2 objects are are in direct physical contact with eachother

Non contact forces

Forces that occur when objects are not physically touching

Balanced forces

When the resultant force is 0 - forces in both directions are equal

Unbalanced forces

When the resultant force is more than 0

Newton’s 1st law

An object will either coninue to move in the same direction at the the same speed OR remain stationary unless a resultant force is added to change the motion of an object

Newton’s 2nd law

Non zero resultant forces acting on an object cause the object to accelerate. Acceleration depends on

• Size of the force

• Mass of the object

Mass

The quantity of matter in an object

Weight

The force an object exerts due to gravity

Centripetal force

The resultant force of an object that moves in a circular motion, acting towards the centre of the circle. Keeps the object moving in a circle.

Inertia

The tendency to keep moving with the same velocity

Inertial mass

Measures how difficult it is to change the velocity of an object

Newton’s 3rd law

When two objects interact, the forces they exert on one another have an equal and opposite reaction

Momentum

The tendency of an object to keep moving

Conservation of momentum

The total momentum before collision is equal to the total momentum after

Stopping distance

The distance a vehicle covers between a drivers first spotting of a hazard and the vehicle actually coming to complete spot

Thinking distance

Distance travelled by the vehicle in the time it takes for the driver to react

Braking distance

Distance travelled by the vehicle after brakes are applied, but before it comes to a complete stop

Work done

Energy is transferred