Figure shows the velocity-displacement curve for an object moving along a straight line. At which of the points marked is the object speeding up?

Options

A. 1
B. 2
C. 1 and 3
D. 1 and 2

Answer

A

Explanation

` a= v (dv)/(dx) =v xx ` (slope of tangent in v- x graph )
Note : v is positive at all the point, So, the sign of acceleration depends on the slope.
At point 1 : slope ` gt 0 rArr a gt 0 and v gt 0 " "rArr ` speed increases.
At point 2 : Slope ` = 0 rArr a = 0 `
At point 3: Slope =0` rArr a lt 0 and v gt 0 rArr " "` Speed decreases.
Note : At point 2, velocity is attaining a maximum value as it decreases, later.