Question

The distance-time graph of a motorcycle is shown in
the figure. When was the motorcycle travelling at a
speed of 2 m s-19
A. 2.55
B. 5,0 s
C. 8.Os
D. 10,5 s
​

Answer 1

Answer:

Option D - 10.5 s

Step-by-step explanation:

On a distance time graph, the speed is the gradient (distance / time) of the line.

In the first part of the graph, distance at 0s = 3m and distance at 4.5s = 3m

∴The gradient of this line = (3 - 3) / (4.5 - 0)= 0 / 4.5 = 0 m/s.

In other words the motor cycle is stationary.

In the second part of the graph, distance at 4.5s = 3m and distance at 9s = 6m

∴The gradient of this line = (6 - 3) / (9 - 4.5)= 3 / 4.5 = 0.67 m/s.

In other words the speed of the motor cycle is 0.67 m/s.

In the third part of the graph, distance at 9s = 6m and distance at 12s = 12m

∴The gradient of this line = (12 - 6) / (12 - 9)= 6 / 3 = 2 m/s.

In other words the speed of the motor cycle is 2 m/s.

So, the motorcycle was travelling at a speed of 2 m/s between 9s to 12s.

∴The answer to this question is Option D - 10.5 s