Laws Of Motion - Mechanics - Physics Previous Year Questions

An object with mass \(5 \mathrm{~kg}\) is acted upon by a force, \(\mathbf{F}=(-3 \hat{\mathbf{i}}-4 \hat{\mathbf{j}}) \mathrm{N}\). If its initial velocity at \(t=0\) is \(\mathbf{v}=(3 \hat{\mathbf{i}}+12 \hat{\mathbf{j}}) \mathrm{m} / \mathrm{s}\), the time at which it will just have a velocity along \(y\)-axis is -

Two masses of \(5 \mathrm{~kg}\) and \(3 \mathrm{~kg}\) are suspended with the help of massless inextensible strings as shown in figure below.

When whole system is going upwards with acceleration \(2 \mathrm{~m} / \mathrm{s}^2\), the value of \(T_1\) is (use, \(g=9.8 \mathrm{~m} / \mathrm{s}^2\))

A body of mass \(10 \mathrm{~kg}\) is kept on a horizontal surface. The coefficient of kinetic friction between the body and the surface is 0.5. A horizontal force of \(60 \mathrm{~N}\) is applied on the body. The resulting acceleration of the body is about

A block of certain mass is placed on a rough inclined plane. The angle between the plane and the horizontal is 30$^\circ$. The coefficients of static and kinetic frictions between the block and the inclined plane are 0.6 and 0.5 respectively. Then, the magnitude of the acceleration of the block is [Take g = 10 ms$^{-2}$]

A wooden block of mass M lies on a rough floor. Another wooden block of the same mass is hanging from the point O through strings as shown in the figure. To achieve equilibrium, the co-efficient of static friction between the block on the floor with the floor itself is

A block of certain mass is placed on a rough floor. The coefficients of static and kinetic friction between the block and the floor are 0.4 and 0.25 respectively. A constant horizontal force $\mathrm{F}=20 \mathrm{~N}$ acts on it so that the velocity of the block varies with time according to the following graph. The mass of the block is nearly (Take $\mathrm{g} \simeq 10 \mathrm{~ms}^{-2}$ )