Speed, velocity and acceleration

Overview

Speed, velocity, acceleration and deceleration with their equations, worked examples for a sprinter, swimmer, long jumper, rower and cyclist, changing direction at constant speed, and what average speed hides.

What you need to know

Answer each one before you reveal it.

Questions from this subtopic

Each one with the model answer underneath.

1. 1

   Define speed and give the equation.

   Model answer

   Speed is the rate of change of distance. Speed = distance ÷ time, measured in metres per second (m s⁻¹).

2. 2

   Define velocity and give the equation.

   Model answer

   Velocity is the rate of change of displacement. Velocity = displacement ÷ time, measured in m s⁻¹ in a stated direction.

3. 3

   A sprinter runs 100 m in 10.5 s. Calculate the average speed.

   Model answer

   The average speed is 9.52 m s⁻¹. Speed = 100 m ÷ 10.5 s = 9.52 m s⁻¹.

4. 4

   A swimmer completes a 200 m race in a 50 m pool in 120 s. Calculate the average speed and the average velocity.

   Model answer

   The average speed is 1.67 m s⁻¹, from 200 m ÷ 120 s. The average velocity is 0 m s⁻¹, because the swimmer finishes at the starting wall.

5. 5

   A long jumper runs 40 m down a straight runway in 4.4 s. What is the average velocity?

   Model answer

   The average velocity is 9.09 m s⁻¹ along the runway. Velocity = 40 m ÷ 4.4 s = 9.09 m s⁻¹.

6. 6

   How long does a rower averaging 5 m s⁻¹ take to cover 2,000 m?

   Model answer

   The rower takes 400 s, or 6 minutes 40 seconds. Time = 2,000 m ÷ 5 m s⁻¹ = 400 s.

Other ways to work this

The same content, four other ways.

What is inside Levo

Six ways to work the same material.