A small mass attached to a string rotates on a frictionless table top as shown. If the tension in the string is increased by pulling the string causing the radius of the circular motion to decrease by a factor of 2, the kinetic energy of the mass will:
1. decrease by a factor of 2
2. remain constant
3. increase by a factor of 2
4. increase by a factor of 4
A conveyor belt is moving at a constant speed of \(2\) m/s. A box is gently dropped on it. The coefficient of friction between them is \(\mu = 0.5\). The distance that the box will move relative to the belt before coming to rest on it, taking \(g = 10\) ms–2 is:
1. | \(0.4\) m | 2. | \(1.2\) m |
3. | \(0.6\) m | 4. | zero |
A car of mass \(m\) is moving on a level circular track of radius \(R\). If \(\mu_s\) represents the static friction between the road and tyres of the car, the maximum speed of the car in circular motion is given by:
1. \(\sqrt{\frac{Rg}{\mu_s} }\)
2. \(\sqrt{\frac{mRg}{\mu_s}}\)
3. \(\sqrt{\mu_s Rg}\)
4. \(\sqrt{\mu_s m Rg}\)
Two masses as shown are suspended from a massless pulley. What would be the acceleration of the system when masses are left free?
1. \(2g/3\)
2. \(g/3\)
3. \(g/9\)
4. \(g/7\)
(where \(g\) is the acceleration due to gravity.)
A body of mass 3 kg hits a wall at an angle of 60º & returns at the same angle. The impact time was 0.2 s. Calculate the force exerted on the wall.
1. 150 N
2. 50 N
3. 100 N
4. 75 N
A mass of 1 kg is thrown up with a velocity of 100 m/s. After 5 seconds, it explodes into two parts. One part of mass 400 g comes down with a velocity of 25 m/s. Calculate the velocity of the other part.
1. 40 m/s upward
2. 40 m/s downward
3. 100 m/s upward
4. 60 m/s downward
A mass is performing a vertical circular motion (see figure.) If the average velocity of the particle is increased, then at which point the string will break?
1. | A | 2. | B |
3. | C | 4. | D |
If force \(F=500-100t,\) then the function of impulse with time will be:
1. \( 500 t-50 t^2 \)
2. \( 50 t-10 \)
3. \( 50-t^2 \)
4. \( 100 t^2\)
A man is slipping on a frictionless inclined plane & a bag falls down from the same height. Then the speed of both is related as:
1. VB > Vm
2. VB < Vm
3. VB = Vm
4. VB and Vm can't be related
A particle of mass m is tied to a string of length \(l\) and whirled into a horizontal plane. If the tension in the string is T, then the speed of the particle will be:
1.
2.
3.
4.