A ball of mass \(0.1~\text{kg}\) is whirled in a horizontal circle of radius \(1\) m by means of a string at an initial speed of \(10~\text{rpm}\) . Keeping the radius constant, the tension in the string is reduced to one quarter of its initial value. The new speed is:
1. | \(5~\text{rpm}\) | 2. | \(10~\text{rpm}\) |
3. | \(20~\text{rpm}\) | 4. | \(14~\text{rpm}\) |
A point mass \(m\) is suspended from a light thread of length \(l,\) fixed at \(O\), and is whirled in a horizontal circle at a constant speed as shown. From your point of view, stationary with respect to the mass, the forces on the mass are:
1. | 2. | ||
3. | 4. |
A car is moving in a circular horizontal track of radius \(10~\text{m}\) with a constant speed of \(10~\text{m/s}\). A plumb bob is suspended from the roof of the car by a light rigid rod of length \(1.00~\text{m}\). The angle formed by the rod with respect to the vertical is:
1. | zero | 2. | \(30^{\circ}\) |
3. | \(45^{\circ}\) | 4. | \(60^{\circ}\) |
A particle moves in the XY-plane under the action of a force \(F\) such that the components of its linear momentum \(p\) at any time \(t\) are \(p_x = 2 \cos t\), \(p_y = 2 \sin t\). The angle between \(F\) and \(p\) at time \(t\) will be:
1. | \(90^{\circ}\) | 2. | \(0^{\circ}\) |
3. | \(180^{\circ}\) | 4. | \(30^{\circ}\) |
A lift is going up. The total mass of lift and the passenger is \(1500\) kg. The variation in the speed of the lift is as given in the graph. The tension in the rope pulling the lift at \(t=11^{\text{th}}\) s will be:
1. \(17400\) N
2. \(14700\) N
3. \(12000\) N
4. zero
The pulleys and strings shown in the figure are smooth and of negligible mass. For the system to remain in equilibrium, the angle \(\theta\) should be:
1. \(0^\circ\)
2. \(30^\circ\)
3. \(45^\circ\)
4. \(60^\circ\)
A string of negligible mass going over a clamped pulley of mass \(m\) supports a block of mass \(M\) as shown in the figure. The force on the pulley by the clamp is given by:
1. \(\sqrt{2} M g\)
2. \(\sqrt{2} m g\)
3. \(g\sqrt{\left( M + m \right)^{2} + m^{2}}\)
4. \(g\sqrt{\left(M + m \right)^{2} + M^{2}}\)
A block \(B\) is placed on top of block \(A\). The mass of block \(B\) is less than the mass of block \(A\). Friction exists between the blocks, whereas the ground on which block \(A\) is placed is assumed to be smooth. A horizontal force \(F\), increasing linearly with time begins to act on \(B\). The acceleration \(a_A\) and \(a_B\) of blocks \(A\) and \(B\) respectively are plotted against \(t\). The correctly plotted graph is:
1. | 2. | ||
3. | 4. |
The variation of momentum with the time of one of the bodies in a two-body collision is shown in fig. The instantaneous force is the maximum corresponding to the point:
1. \(P\)
2. \(Q\)
3. \(R\)
4. \(S\)
A uniform chain of length \(L\) hangs partly from a table which is kept in equilibrium by friction. If the maximum length that can be supported without slipping is \(l,\) then the coefficient of friction between the table and the chain is:
1. \(\frac{l}{L}\)
2. \(\frac{l}{L+l}\)
3. \(\frac{l}{L-l}\)
4. \(\frac{L}{L+l}\)