A man of mass \(60\) kg is standing on the ground and holding a string passing over a system of ideal pulleys. A mass of \(10\) kg is hanging over a light pulley such that the system is in equilibrium. The force exerted by the ground on the man is: (\(g=\) acceleration due to gravity)
1. \(20\) g
2. \(45\) g
3. \(40\) g
4. \(60\) g
A small coin is kept at a distance r from the centre of a gramophone disc rotating at an angular speed . The minimum coefficient of friction for which a coin will not slip is:
1.
2.
3.
4.
A plank with a box on it at one end is gradually raised at the other end. As the angle of inclination with the horizontal reaches 30°, the box starts to slip and slides 4.0 m down the plank in 4.0 s. The coefficients of static and kinetic friction between the box and the plank, respectively, will be:
1. | 0.6 and 0.6 | 2. | 0.6 and 0.5 |
3. | 0.5 and 0.6 | 4. | 0.4 and 0.3 |
A block \(A\) of mass 7 kg is placed on a frictionless table. A thread tied to it passes over a frictionless pulley and carries a body \(B\) of mass 3 kg at the other end. The acceleration of the system will be: (given \(g\) = 10 ms–2)
1. | 100 ms–2 | 2. | 3 ms–2 |
3. | 10 ms–2 | 4. | 30 ms–2 |
Two masses, M and m, are attached to a vertical axis by weightless threads of combined length l. They are set in rotational motion in a horizontal plane about this axis with constant angular velocity ω. If the tensions in the threads are the same during motion, the distance of M from the axis is:
1.
2.
3.
4.
A motorcycle is going on an overbridge of radius R. The driver maintains a constant speed. The normal force on the motorcycle as it ascends the overbridge will be:
1. increases.
2. decreases.
3. remains the same.
4. fluctuates erratically.
A block is placed on a rough horizontal plane. A time dependent horizontal force, \(F=kt,\) acts on the block. The acceleration time graph of the block is :
1. | 2. | ||
3. | 4. |
The figure shows a rod of length 5 m. Its ends, A and B, are restrained to moving in horizontal and vertical guides. When the end A is 3 m above O, it moves at 4 m/s. The velocity of end B at that instant is:
1. 2 m/s
2. 3 m/s
3. 4 m/s
4. 0.20 m/s
If the block is being pulled by the rope moving at speed v as shown, then the horizontal velocity of the block is:
1. v
2. vcos
3.
4.
In the given figure, spring balance is massless, so the reading of spring balance will be:
1. | 2 kg | 2. | 3.5 kg |
3. | 2.9 kg | 4. | 3.1 kg |