A parachutist falls downward with an acceleration of \(2~\text{m/s}^2\) at a height of \(200\) m from the ground. Calculate the upthrust of air if the mass of the parachutist is \(60\) kg: (assume \(g= 10~\text{m/s}^2)\)
1. \(480\) N
2. \(620\) N
3. \(720\) N
4. \(600\) N

What is the minimum value of force \(F\) such that at least one block leaves the ground in the given figure? \(\left(g=10~\text{m/s}^2\right)\) $\mathrm{}$

The block of mass m (shown in the figure) does not move on applying the inclined force F. The friction force acting on the block is:

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

A particle of mass \(m\) is attached to a string and is moving in a vertical circle. Tension in the string when the particle is at its highest and lowest point is \(T_1\) $\mathrm{and}$ \(T_2\) respectively. Here \(T_2-T_1\) is equal to: 

Choose the incorrect alternative:

A block slides down on a 45° rough incline in thrice the time it takes to slide down on a frictionless 45° incline of the same length. The coefficient of friction between the block and the rough incline is:

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

2.  ${\tan }^{-1}\left(\frac{\mathrm{R}}{\mathrm{S}}\right)$

3.  ${\tan }^{-1}\left(\frac{\mathrm{a}}{\mathrm{R}}\right)$

4.  ${\tan }^{-1}\left(\frac{\mathrm{R}}{\mathrm{a}}\right)$

The tension in the string connecting blocks, \(B\) and \(C\), placed on a smooth horizontal surface in the following diagram is: