JEE Main Laws of Motion Practice Questions With Solutions

A $1\mathrm{kg}$1 \textrm{ } kg mass is suspended from the ceiling by a rope of length $4\mathrm{m}$4 \textrm{ } m. A horizontal force '$F$F' is applied at the mid point of the rope so that the rope makes an angle of ${45}^{\circ }$45^{\circ} with respect to the vertical axis as shown in figure. The magnitude of $F$F is :

(Assume that the system is in equilibrium and $g=10\mathrm{m}/{\mathrm{s}}^2$g = 10 \textrm{ } m / s^{2})

A heavy iron bar, of weight $W$W is having its one end on the ground and the other on the shoulder of a person. The bar makes an angle $\theta$\theta with the horizontal. The weight experienced by the person is :

A light unstretchable string passing over a smooth light pulley connects two blocks of masses $m_1$m_{1} and $m_2$m_{2}. If the acceleration of the system is $\frac{g}{8}$\frac{g}{8}, then the ratio of the masses $\frac{m_2}{m_1}$\frac{m_{2}}{m_{1}} is :

A given object takes $\mathrm{n}$n times the time to slide down ${45}^{\circ }$45^{\circ} rough inclined plane as it takes the time to slide down an identical perfectly smooth ${45}^{\circ }$45^{\circ} inclined plane. The coefficient of kinetic friction between the object and the surface of inclined plane is :

A player caught a cricket ball of mass $150\mathrm{g}$150 \textrm{ } g moving at a speed of $20\mathrm{m}/\mathrm{s}$20 \textrm{ } m / s. If the catching process is completed in $0.1\mathrm{s}$0.1 \textrm{ } s, the magnitude of force exerted by the ball on the hand of the player is:

Three bodies A, B and C have equal kinetic energies and their masses are $400\mathrm{g},1.2\mathrm{kg}$400 \textrm{ } g , 1.2 \textrm{ } kg and $1.6\mathrm{kg}$1.6 \textrm{ } kg respectively. The ratio of their linear momenta is :

A body of weight $200\mathrm{N}$200 \textrm{ } N is suspended from a tree branch through a chain of mass $10\mathrm{kg}$10 \textrm{ } kg. The branch pulls the chain by a force equal to (if $\mathrm{g}=10\mathrm{m}/{\mathrm{s}}^2$g = 10 \textrm{ } m / s^{2}) :

A light string passing over a smooth light pulley connects two blocks of masses $m_1$m_{1} and $m_2($m_{2} \left(\right. where $m_2>m_1)$m_{2} > m_{1} \left.\right). If the acceleration of the system is $\frac{g}{\sqrt{2}}$\frac{g}{\sqrt{2}}, then the ratio of the masses $\frac{m_1}{m_2}$\frac{m_{1}}{m_{2}} is:

A particle moves in $x$x-$y$y plane under the influence of a force $\overrightarrow{F}$\overset{\rightarrow}{F} such that its linear momentum is $\overrightarrow{\mathrm{p}}(\mathrm{t})=\hat{i}\cos (\mathrm{kt})-\hat{j}\sin (\mathrm{kt})$\overset{\rightarrow}{p} \left(\right. t \left.\right) = \hat{i} cos ⁡ \left(\right. kt \left.\right) - \hat{j} sin ⁡ \left(\right. kt \left.\right). If $\mathrm{k}$k is constant, the angle between $\overrightarrow{\mathrm{F}}$\overset{\rightarrow}{F} and $\overrightarrow{\mathrm{p}}$\overset{\rightarrow}{p} will be :

A heavy box of mass $50\mathrm{kg}$50 \textrm{ } kg is moving on a horizontal surface. If co-efficient of kinetic friction between the box and horizontal surface is 0.3 then force of kinetic friction is :