To describe motion you need numbers and pictures. Speed and acceleration give the numbers; distance-time and speed-time graphs give the pictures.
Speed = distance ÷ time. Average speed uses the total distance and total time. Acceleration = change in speed ÷ time taken, in m/s². A negative acceleration (deceleration) means slowing down.
On a distance-time graph the gradient is the speed; a flat line means stationary; a steeper line means faster. On a speed-time graph the gradient is the acceleration, a flat line is constant speed, and the area under the line is the distance travelled.
A flat line on a distance-time graph means the object is:
On a speed-time graph, the gradient shows:
The area under a speed-time graph gives:
A cyclist travels 150 km in 2 hours.
What is the average speed, in km/h?
Enter an exact answer, without rounding.A car speeds up from 0 to 20 m/s in 5 s.
What is the acceleration, in m/s²?
Enter an exact answer, without rounding.A runner moves at a constant 10 m/s for 6 s.
How far does she travel, in m?
Enter an exact answer, without rounding.A train slows from 30 m/s to 10 m/s in 4 s.
What is its acceleration, in m/s²?
Enter an exact answer, without rounding.A car accelerates from 0 to 8 m/s in 4 s (a straight sloping line).
How far does it travel, in m?
Enter an exact answer, without rounding.Speed is calculated as:
The units of acceleration are:
A steeper line on a distance-time graph means:
A sloping upward straight line on a speed-time graph means:
A negative acceleration means the object is:
Questions from every topic in this course. Pick an answer for each one, then hit Check My Answers.
A bus travels 90 km in 1.5 hours. Its average speed is:
A car goes from 0 to 20 m/s in 4 s. Its acceleration is:
On a distance–time graph, a steeper straight line means:
On a speed–time graph, the area under the line gives:
A runner covers 400 m in 80 s. The average speed is:
A horizontal line on a speed–time graph shows:
A bike slows from 12 m/s to 4 m/s in 2 s. Its acceleration is:
72 km/h in m/s is: