A body is moving with a velocity of \(2\hat i\) m/s. If the force acting on the body is \((2\hat i+3\hat j+3\hat k)\) N, then the momentum of the body is changing in:
1. \(X\)-direction only
2. \(X\text-Y\) directions
3. \(Y\text-Z\) directions
4. In all \(X\text-Y\text-Z\) directions
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? \(\left(g=10~\text{m/s}^2\right)\)
1. | \(20~\text{N}, 2~\text{kg}\) leaves the ground first. |
2. | \(30~\text{N}, 3~\text{kg}\) leaves the ground first. |
3. | \(40~\text{N}, 2~\text{kg}\) leaves the ground first. |
4. | \(50~\text{N}, 3~\text{kg}\) leaves the ground first. |
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:
1. \(F \cos\theta\)
2. \(F \sin\theta\)
3. \(\mu mg-F \sin\theta\)
4. \(\mu mg\)
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:
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. |
A block slides down on a \(45^{\circ}\) rough incline in thrice the time it takes to slide down on a frictionless \(45^{\circ}\) incline of the same length. The coefficient of friction between the block and the rough incline is:
1. | \(0.6\) | 2. | \(0.7\) |
3. | \(0.5\) | 4. | \(0.9\) |
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.
The tension in the string connecting blocks, \(B\) and \(C\), placed on a smooth horizontal surface in the following diagram is:
1. | \(25\) N | 2. | \(30\) N |
3. | \(32.5\) N | 4. | \(37.5\) N |