Physics IGCSE - Motion

Scalar

only has magnitude (size)

Vector

has magnitude and direction

Speed

distance covered per unit time (scalar)

SIU = m/s

Speed formula

average speed = distance moved (m)/time (s)

Velocity

speed of an object as well as direction (vector)

Acceleration

rate of change of objects velocity (vector)

SIU: (m/s^2)

Acceleration

average acceleration = final velocity - initial velocity/time

Free fall

The acceleration due to free fall ,g, near the Earth's surface has a constant value of 9.8 m/s

All objects falling towards Earth have an acceleration of 9.8 m/s

Mass

measure of quantity of matter in an object (kg)

Weight

Gravitation force that acts on an object with mass.

SIU: Newtons (N)

Measured: Force meter

Gravitational force

GFS (g), is defines as force per unit mass.

SIU: Newtons per kilogram (N/kg)

Gravitational force formula

gravitational field strength (N/kg) = force (N)/mass (kg)

1 N/kg = 1m/s-2

Weight formula

Weight (N) = mass (kg) x GFS (N/kg)

W = mg

Density

How much mass there is within a certain volume

SIU: kilograms per cubic meter (kg/m3)

Density formula

density (kg/m3) = mass (kg)/volume (m3)

p=m/V

Pressure

force per unit area acting on a surface

SIU: Pascal (Pa)

Pressure formula

Pressure = force/area

Sketch, plot and interpret distance–time

Sketch, plot and interpret speed–time graphs

Correlation with acceleration

increasing speed → accelerating

decreasing speed → decelerating

Determine from the shape of a graph when an object is at rest

Determine from the shape of a graph when an object is moving with constant speed

Determine from the shape of a graph when an object is accelerating

Determine from the shape of a graph when an object is deceleration

Calculate speed from the gradient of a straight-line section of a distance–time graph

Calculate acceleration from the gradient of a straight-line section of a speed–time graph