A body of mass \(M\) hits normally a rigid wall with velocity \(v\) and bounces back with the same velocity. The impulse experienced by the body is:
1. \(1.5Mv\)
2. \(2Mv\)
3. zero
4. \(Mv\)
A block of mass \(m\) is in contact with the cart \((C)\) as shown in the figure.
The coefficient of static friction between the block and the cart is \(\mu.\) The acceleration \(a\) of the cart that will prevent the block from falling satisfies:
1. \(a > \frac{mg}{\mu}\)
2. \(a > \frac{g}{\mu m}\)
3. \(a \ge \frac{g}{\mu}\)
4. \(a < \frac{g}{\mu}\)
A gramophone record is revolving with an angular velocity . A coin is placed at a distance r from the centre of the record. The static coefficient of friction is . The coin will revolve with the record if:
1.
2.
3.
4.
An explosion blows a rock into three parts. Two parts go off at right angles to each other. These two are, the first part 1 kg moving with a velocity of 12 and the second part 2 kg moving with a velocity of 8 . If the third part flies off with a velocity of 4 , its mass would be:
1. 5 kg
2. 7 kg
3. 17 kg
4. 3 kg
The mass of a lift is \(2000\) kg. When the tension in the supporting cable is \(28000\) N, then its acceleration is:
(Take \(g=10\) m/s2)
1. | \(30\) ms-2 downwards | 2. | \(4\) ms-2 upwards |
3. | \(4\) ms-2 downwards | 4. | \(14\) ms-2 upwards |
A body, under the action of a force \(\overset{\rightarrow}{F} = 6 \hat{i} - 8 \hat{j} + 10 \hat{k}\), acquires an acceleration of 1 ms-2. The mass of this body must be:
1. 2 √10 kg
2. 10 kg
3. 20 kg
4. 10 √2 kg
1. | \(14\) m/s and \(15\) m/s |
2. | \(15\) m/s and \(16\) m/s |
3. | \(16\) m/s and \(17\) m/s |
4. | \(13\) m/s and \(14\) m/s |
Sand is being dropped on a conveyor belt at the rate of M kg/s. The force necessary to keep the belt moving with a constant velocity of v m/s will be:
1. Mv Newton
2. 2Mv Newton
3. Newton
4. zero
A block \(B\) is pushed momentarily along a horizontal surface with an initial velocity \(v.\) If \(\mu\) is the coefficient of sliding friction between \(B\) and the surface, the block \(B\) will come to rest after a time:
1. \(v \over g \mu\)
2. \(g \mu \over v\)
3. \(g \over v\)
4. \(v \over g\)