Fundamentally, the normal force between two surfaces in contact is:

1. Electromagnetic

2. Gravitational

3. Weak nuclear force

4. Strong nuclear force

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:

The kinetic energy \(K\) of a particle moving in a circular path varies with the distance covered \(S\) as \(K = aS^2\) 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. \(\tan^{-1}\left(\frac{S}{R}\right)\)
2. \(\tan^{-1}\left(\frac{R}{S}\right)\)
3. \(\tan^{-1}\left(\frac{a}{R}\right)\)
4. \(\tan^{-1}\left(\frac{R}{a}\right)\)

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:

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:

What will be the reading of the spring balance in the given setup?  (take \(g=10~\text{m/s}^2\) )
                

1. \(60~\text N\) 
2. \(40~\text N\)
3.  \(50~\text N\) 
4. \(80~\text N\) 

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. \(180~\text N\) 
2. \(216~\text N\) 
3. \(0\)
4. none of these