Tora is training for a cycling tournament.
The speed-time graph below shows her motion as she cycles along a flat, straight road.
(a) In which section (A, B, C, D, or E) of the speed-time graph is Tora’s acceleration the largest?
(b) Calculate Tora’s acceleration between 5 and 10 seconds.
Part (a)
Step 1: Recall that the slope of a speed-time graph represents the magnitude of acceleration
Step 2: Identify the section with the steepest slope
- Section D of the graph has the steepest slope
Hence, the largest acceleration is shown in section D
Part (b)
Step 1: Recall that the gradient of a speed-time graph gives the acceleration
- Calculating the gradient of a slope on a speed-time graph gives the acceleration for that time period
Step 2: Draw a large gradient triangle at the appropriate section of the graph
- A gradient triangle is drawn for the time period between 5 and 10 seconds below:
Step 3: Calculate the size of the gradient and state this as the acceleration
- The acceleration is given by the gradient, which can be calculated using:
acceleration = gradient = 5 ÷ 5 = 1 m/s2
- Therefore, Tora accelerated at 1 m/s2 between 5 and 10 seconds