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:

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:

A tube of length \( L\) is filled completely with an incompressible liquid of mass \(M\) and closed at both ends. The tube is then rotated in a horizontal plane about one of its ends with a uniform angular velocity \(\omega\). The force exerted by the liquid at the other end is:

A 0.5 kg ball moving with a speed of 12 m/s strikes a hard wall at an angle of ${\mathrm{30°}}^{\mathrm{}}$ with the wall. It is reflected with the same speed and at the same angle. If the ball is in contact with the wall for 0.25 s, the average force acting on the wall is:
              

1. 48 N

2. 24 N

3. 12 N

4. 96 N

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. \(v \over g\)

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.  $\frac{\mathrm{Mv}}{2}$ Newton

4.  zero