Mock Test 1 — Laws of Motion

A force of $10$ N acts on a $2$ kg body for $3$ s. The impulse is:

A man weighs $60$ kg. In a lift moving down at constant velocity, his apparent weight is:

The coefficient of friction between a block and a horizontal surface is $0.5$. The minimum force at $45^\circ$ above horizontal to drag the block (mass $10$ kg, $g = 10$):

Two blocks of $4$ kg and $6$ kg are kept in contact on a smooth surface. A horizontal force of $20$ N is applied to the $4$ kg block. The contact force between them is:

A bullet of mass $20$ g hits a wooden block at $400$ m/s and penetrates $20$ cm. The retarding force is:

A particle in vertical circular motion has a minimum speed of $\sqrt{gr}$ at the top. The string tension at the top is:

An object of mass $m$ slides down a smooth incline of angle $\theta$ from rest. Time to descend a length $L$:

Three blocks A, B, C of masses $3$ kg, $5$ kg, $2$ kg respectively are connected by strings and lie on a smooth horizontal surface. A force $20$ N pulls A. Tension between B and C is:

A wedge of mass $M$ with an angle $\theta$ is free to move on a smooth horizontal surface. A block of mass $m$ placed on its smooth incline slides down. Acceleration of wedge:

A block of mass $5$ kg is suspended by two strings making $30^\circ$ and $60^\circ$ with the horizontal. The tensions ($g = 10$):

A force $F = 2t^3$ N acts on a $1$ kg block. Velocity (m/s) at $t = 2$ s starting from rest:

A man pulls a bag of $5$ kg up a $30^\circ$ rough incline ($\mu = 0.2$) with constant velocity. Force he exerts parallel to incline ($g = 10$, in N):

A block of mass $2$ kg on a horizontal surface with $\mu_s = 0.6$, $\mu_k = 0.4$. A horizontal force of $14$ N is applied. The friction force on the block (in N) is:

Assertion (A): Friction can act on a body even when there is no relative motion between surfaces. Reason (R): Static friction is self-adjusting to oppose the tendency of relative motion.

Assertion (A): Centripetal force is a real force acting on a body in circular motion. Reason (R): A real physical agency (tension, friction, gravity, normal) provides the centripetal force.