A coin placed on a rotating table just slips if it is placed at a distance 4r from the center. On doubling the angular velocity of the table, the coin will just slip when the distance from the centre is equal to:-
1. 4r
2. 2r
3. r
4.
A massless string of length 1 m fixed at one end carries a mass of 2 kg at the other end. The string makes rev/s around the axis through the fixed end as shown in the figure. The tension on the string will be:
1. | 32 N | 2. | 3 N |
3. | 16 N | 4. | 4 N |
Three blocks A, B and C of mass 3M, 2M and M respectively are suspended vertically with the help of springs PQ and TU and a string RS as shown in fig. The acceleration of blocks A, B and C are respectively.
The value of acceleration \(a_{1}\) at the moment string RS is cut will be:
1. g downward
2. g upward
3. more than g downward
4. zero
Two bodies of mass, \(4~\text{kg}\) and \(6~\text{kg}\), are tied to the ends of a massless string. The string passes over a pulley, which is frictionless (see figure). The acceleration of the system in terms of acceleration due to gravity (\(g\)) is:
1. | \(\frac{g}{2}\) | 2. | \(\frac{g}{5}\) |
3. | \(\frac{g}{10}\) | 4. | \(g\) |
A particle is on a smooth horizontal plane. A force F is applied, whose F-t graph is given.
Consider the following statements.
a. At time , acceleration is constant.
b. Initially the particle must be at rest.
c. At time , acceleration is constant.
d. The initial acceleration is zero.
Select the correct statement(s):
1. | (a), (c) | 2. | (a), (b), (d) |
3. | (c), (d) | 4. | (b), (c) |
If between block A and inclined plane is 0.5 and that between block B and the inclined plane is 0.8, then the normal reaction between blocks A and B will be:
1. 180 N
2. 216 N
3. 0
4. None of these
If a young man of mass 60 kg stands on the floor of a lift which is accelerating downwards at 1 , then the reaction of the floor of the lift on the man will be: (g=9.8)
1. | 528 N | 2. | 540 N |
3. | 546 N | 4. | None of these |
An object of mass m is held against a vertical wall by applying horizontal force F as shown in the figure. The minimum value of the force F will be: (Consider friction between wall and object.)
1. Less than mg
2. Equal to mg
3. Greater than mg
4. Cannot determine
Two masses, and are experiencing the same force where < . The ratio of their acceleration is:
1. 1
2. less than 1
3. greater than 1
4. all the three cases
In the diagram, a 100 kg block is moving up with constant velocity. Find out the tension at point P.
1. 1330 N
2. 490 N
3. 1470 N
4. 980 N