Question

In the following displacement x versus time t graph, at which among the points $P,Q$ and $R$ is the object’s speed increasing

• A. R only
• B. P only
• C. Q and R only
• D. P ,Q and R

Answer 1

Answer: (A)

In given displacement-time graph, velocity at a particular point is given by the slope of tangent to curve drawn at that point. Speed is the magnitude of velocity, so magnitude of slope gives speed.

As angle of tangent at $R\left({\theta }_3\right)$ is maximum, so slope's magnitude $|m|=\left|\tan {\theta }_3\right|$ is maximum at $R$. Hence, speed is increasing at point $R$.