The velocity-time graph of a point mass moving in the +x-direction is shown below. The acceleration of the point mass is:

Differentiate Between the Following:

Motion and force of friction.

Sweta swims in a $90 \mathrm{m}$ long pool. She covers $180 \mathrm{m}$ in $90 \mathrm{s}$ by swimming from one end to the other and back along the same straight path. Find the average speed and the average velocity of Sweta.

A body falling from rest describes distance ${\mathrm{S}}_1$, ${\mathrm{S}}_2$ and ${\mathrm{S}}_3$ in the 1^st, 2^nd and 3^rd seconds of its fall. Then the ratio of ${\mathrm{S}}_1:{\mathrm{S}}_2:{\mathrm{S}}_3$ is: