Physics Term 1

Distance

Actual path that is travelled by an object

Scalar quantity

Scalar quantity

Only magnitude

Displacement

How far an object is away from its original position

Vector quantity

Vector quantity

Magnitude and direction

Speed

Scalar quantity

Measure of how fast an object is travelling

Units = m/s or ms to the power of -1

Average speed

Speed between two points in time

Instantaneous speed

Speed at a particular point in time

How to calculate speed

Speed = distance/time

Velocity

Vector quantity

How fast something is travelling and in what direction

How to calculate velocity

Velocity=Displacement/time

Converting km/hr to m/s

%3.6

Km/hr —————> m/s

x3.6

M/s —————→ km/hr

What does a distance-time graph show

How far an object travels over time

Stationary

Constant speed

Increasing speed

Decreasing speed

What does a steeper or flatter gradient show

Steeper gradient = higher speed

Flatter speed = lower speed

Calculating speed

Gradient (speed) = rise (distance travelled)/run (time taken)

Acceleration

The rate at which the velocity of an object changes

Measured in m/s to the power of 2 or ms to the power of -2

Example of Constant acceleration

Car accelerating steadily on a high way

Object in freefall

Example of non-constant acceleration

Parachute slowing as drag increases

Rocket launching

Deceleration

Negative acceleration = rate at which the velocity slows down

How to calculate average acceleration

Change in velocity (final velocity - initial velocity)/ time taken

What is gravity

Pulls all objects toward the centre of the earth

g = 9.8m/s squared, when a body falls freely

Constant velocity

Increasing acceleration

Constant acceleration

Speed-time graphs

Displays speed of an object

Can be used to calculate distance travelled by an object and acceleration

Acceleration

Deceleration

Constant speed

Stationary

What represents distance travelled

The area under a speed-time graph