A block of mass $m$ is pulled along a horizontal surface by applying a force at an angle $\theta$ with the horizontal. If the block travels with a uniform velocity $u$ and has a displacement $s$ and the coefficient of friction is $\mu$, then, the work done by the applied force is

Assertion: A horse has to pull a cart harder during the first few steps of his motion.

Reason: The first few steps are always difficult.

Consider a liquid at rest in a container which opens into the atmosphere. At any point $A$ at a depth $h$ below the surface of the liquid,

(i) the gauge pressure at point $A$ is $\rho gh$.

(ii) the gauge pressure at point $A$ is $P_{\mathrm{a}}+\rho gh$.

(iii) The pressure at point $A$ is $\rho gh$.

(iv) The pressure at point $A$ is $P_{\mathrm{a}}+\rho gh$.

The correct alternative is