If a young man of mass \(60\) kg stands on the floor of a lift which is accelerating downwards at \(1~\text{m/s}^2\), then the reaction of the floor of the lift on the man will be: \(\left(g = 9.8~\text{m/s}^2 \right)\)
1. | \(528\) N | 2. | \(540\) N |
3. | \(546\) N | 4. | None of these |
If \(\mu\) 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
A particle is on a smooth horizontal plane. A force \(F\) is applied, whose \((F\text-t)\) graph is given.
Consider the following statements.
(a) | At time \(t_1\), acceleration is constant. |
(b) | Initially the particle must be at rest. |
(c) | At time \(t_2\), 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) |
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. \(\frac{r}{4}\)
A massless string of length \(1\) m fixed at one end carries a mass of \(2\) kg at the other end. The string makes \(\frac{2}{\pi}\) 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 \(\mathrm{PQ}\) and \(\mathrm{TU}\) and a string \(\mathrm{RS}\) as shown in fig. The acceleration of blocks \(A\), \(B\) and \(C\) are \(a_{1} , a_{2}~ \text{and}~ a_{3}\) respectively.
The value of acceleration \(a_{1}\) at the moment string \(\mathrm{RS}\) 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. | \(\dfrac{g}{2}\) | 2. | \(\dfrac{g}{5}\) |
3. | \(\dfrac{g}{10}\) | 4. | \(g\) |
In the diagram, a \(100\) kg block is moving up with constant velocity. Find out the tension at the point \(P\).
1. \(1330\) N
2. \(490\) N
3. \(1470\) N
4. \(980\) N
Calculate the reading of the spring balance shown in the figure: (take \(g=10\) m/s2)
1. \(60\) N
2. \(40\) N
3. \(50\) N
4. \(80\) N
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