# motion in 1 dimension question ?

This is the x-t graph of

the motion of a

particle. Of the four

points P, Q, R, and S,

the acceleration a is greatest (most positive)

at

### 2 Answers

- AmyLv 71 month ago
Acceleration is the second derivative of position (x).

Estimate how the velocity (slope) is changing at each of the points. E.g. it's changing slowly at point P, which means acceleration is close to zero.

- billrussell42Lv 71 month ago
velocity is the slope of the curve, the first derivative. Acceleration is the slope of the slope, the second derivative. The latter is difficult to see....

but the velocity starts at zero, increases to P then decreases until Q where the velocity is zero. It then increases in the negative direction, maximizing at P and goes back to zero at S.

Given that, I would have to guess at P being where the acceleration is max positive... if I had to pick one of those points... but I'd pick somewhere between R and S as the actual max. See below. Acc is slope of the red curve...