2.6–2.7: Speed and distance-time graphs

What is the equation for average speed?

Average speed = distance travelled ÷ time taken.

What is the equation for distance travelled?

Distance travelled = average speed × time taken.

What is the equation for time taken?

Time taken = distance travelled ÷ average speed.

What is the unit of speed?

Metres per second (m/s).

What is the unit of distance?

Metres (m).

What is the unit of time in the speed equation?

Seconds (s).

How do you calculate speed from a distance-time graph?

Calculate the gradient: change in distance ÷ change in time.

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

Speed.

What does a horizontal line on a distance-time graph mean?

The object is stationary because its distance is not changing.

What does a straight sloping line on a distance-time graph mean?

The object is moving at constant speed.

What does a steeper gradient on a distance-time graph mean?

A greater speed.

How do you calculate average speed over a journey?

Total distance travelled ÷ total time taken.

Convert 2 minutes into seconds.

120 seconds.

A car travels 150 m in 10 s. Calculate its average speed.

150 ÷ 10 = 15 m/s.

A runner travels at 4 m/s for 12 s. Calculate the distance travelled.

4 × 12 = 48 m.

A cyclist travels 200 m at 5 m/s. Calculate the time taken.

200 ÷ 5 = 40 s.