Displacement-time curve of a particle moving along a straight line is shown. Tangents at `A` and `B` makes angle `45^(@)` and `135^(@)` with positive `x`-axis respectively. The average acceleration of the particle during `t=1,t=2` seconds is

Options

A. `- 2 m//s^(2)`
B. `1 m//s^(2)`
C. `-1 m//s^(2)`
D. zero

Answer

A

Explanation

`a_(av)=(V_(f)-V_(i))/(Delta t)=("(Slope at B)"-"(Slope at A)")/(1s) `
`=(-1-1)/1=-2 m//s^(2)`