Edexcel IGCSE Physics - Forces and motion

What is a scalar quantity?

A quantity with magnitude only (no direction)

What is a vector quantity?

A quantity with magnitude and direction

Equation to find speed

^{Speed = distance / time}

^{v = d / t}

Units for mass (m)

Kilogram

(Kg)

Unit for distance (d) or displacement (s)

Metre

(M)

Unit for speed (s) or velocity (v)

metre/second

(m/s)

Unit for acceleration (a)

metre/second²
(m/s²)

Unit for force (F)

Newton

(N)

Unit for time (t)

Second

(s)

Unit for gravitational field strength

Newton/kilogram

(N/kg)

What does the gradient of a distance-time graph represent?

the speed
- flat line means stationary
- straight line means constant speed
- curved line means accelerating
the steeper the line, the faster the object is moving

Equation to find acceleration

acceleration = change in velocity/time taken
a = (v-u) / t

What does the gradient of a velocity-time graph represent?

- Gradient means acceleration
- Flat line means constant velocity
- Straight line means constant acceleration (changing velocity)

What does the area underneath the line in a velocity-time graph represent?

Area under the line represents distance travelled

Equation to find final speed

(final speed)² = (initial speed)² + (2 x acceleration x distance)
v² = u² + (2 x a x s)