The distance-time graph of a motorcycle is shown in the figure. When was the motorcycle travelling at a speed of 2 `ms^(-1)`?

Options

A. 2.5 s
B. 5.0 s
C. 8.0 s
D. 10.5 s

Answer

D

Explanation

From the given distance-time graph of a motorcycle, initially distance was same, for time interval 0 to 3 s. Hence speed of motorcycle was zero and it was in rest.
From 3 m to 6 m, motorcycle was moving with uniform speed but it took more than 3 s, so speed would be less than 1 m `s^(-1)`. From 6 m to 12 m, motorcycle was also moving with uniform speed.
`therefore` Speed of motorcycle = `("Change in distance")/("Change in time")`
= `((12-6)m)/((12-9)s)=(6m)/(3s)=2ms^(-1)`
Hence the motorcycle was travelling at a speed of 2 m `s^(-1)` at 10.5 s.