The velocity -time `(v - t)` graph of a particle moving in a straight line is shown in figure. The acceleration of the particle at `t = 9` is:

Options

A. zero
B. `5 ms^(-2)`
C. `-5 ms^(2)`
D. `-2 ms^(-2)`

Answer

C

Explanation

Acceleration between 8 to 10 s (or at `t = 9s`).
`a = (V_(2) - V_(1))/(t_(2) - t_(1)) = (5 - 15)/(10 - 8) = - 5 m//s^(2)`