A particle of mass \(m\) is suspended from a ceiling through a massless string. The particle moves in a horizontal circle as shown in the given figure. The tension in the string is:
1. \(mg\)
2. \(2mg\)
3. \(3mg\)
4. \(4mg\)
Choose the incorrect alternative:
1. | Newton's first law is the law of inertia. |
2. | Newton's first law states that if the net force on a system is zero, the acceleration of any particle of the system is not zero. |
3. | Action and reaction act simultaneously. |
4. | The area under the force-time graph is equal to the change in momentum. |
The kinetic energy 'K' of a particle moving in a circular path varies with the distance covered S as K = a, where a is constant. The angle between the tangential force and the net force acting on the particle is: (R is the radius of the circular path)
1.
2.
3.
4.
A simple pendulum hangs from the roof of a train moving on horizontal rails. If the string is inclined towards the front of the train, then the train is:
1. | moving with constant velocity. |
2. | in accelerated motion. |
3. | in retarded motion. |
4. | at rest. |
A body of mass \(m\) is moving on a concave bridge \(ABC\) of the radius of curvature \(R\) at a speed \(v\). The normal reaction of the bridge on the body at the instant it is at the lowest point of the bridge is:
1. \(mg-\frac{mv^{2}}{R}\)
2. \(mg+\frac{mv^{2}}{R}\)
3. \(mg\)
4. \(\frac{mv^{2}}{R}\)
The angle of banking for a cyclist taking a turn at a curve is given by \(\tan\theta = \frac{v^{n}}{rg}\) where symbols have their usual meaning. The value of \(n\) is:
1. | \(1\)
|
2. | \(2\)
|
3. | \(3\)
|
4. | \(4\) |
1. |
\(\overrightarrow N+\overrightarrow T+\overrightarrow W=0\) |
2. | \(T^2=N^2+W^2\) |
3. | \(T = N + W\) | 4. | \(N = W \tan \theta\) |
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
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
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