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. |
If two forces ( ) and ( ) N are acting on a body of mass 2 kg, then the acceleration produced in the body in will be:
1. ( )
2. ( )
3. ( )
4. ( )
A body of mass 5 kg is acted upon by two perpendicular forces, 8 N and 6 N. The magnitude of the acceleration of the body is:
1. | 0.99 ms-2 | 2. | 3 ms-2 |
3. | 2 ms-2 | 4. | 0.77 ms-2 |
The force 'F' acting on a particle of mass 'm' is indicated by the force-time graph shown below. The change in momentum of the particle over the time interval from 0 to 8 s is:
1. | 24 Ns | 2. | 20 Ns |
3. | 12 Ns | 4. | 6 Ns |
On the application of an impulsive force, a sphere of mass \(500\) g starts moving with an acceleration of \(10\) m/s2. The force acts on it for \(0.5\) s. The gain in the momentum of the sphere will be:
1. \(2.5\) kg-m/s
2. \(5\) kg-m/s
3. \(0.05\) kg-m/s
4. \(25\) kg-m/s
Two masses, and are experiencing the same force where < . The ratio of their acceleration is:
1. 1
2. less than 1
3. greater than 1
4. all the three cases
An impulse of 6m is applied to a body of mass m moving with velocity \(\hat i+2\hat j\). The final velocity of the body will be:
1.
2.
3.
4.
A 100 kg gun fires a ball of 1 kg horizontally from a cliff at a height of 500 m. It falls on the ground at a distance of 400 m from the bottom of the cliff. The recoil velocity of the gun is: (Take g = 10 m/s2)
1. 0.2 m/s
2. 0.4 m/s
3. 0.6 m/s
4. 0.8 m/s
An object of mass 3 kg is at rest. Now if a force of \(\overset{\rightarrow}{F} = 6 t^{2} \hat{i} + 4 t \hat{j}\) is applied to the object, then the velocity of the object at t = 3 second will be :
1. \(18 \hat{i} + 3 \hat{j}\)
2. \(18 \hat{i} + 6 \hat{j}\)
3. \(3 \hat{i} + 18 \hat{j}\)
4. \(18 \hat{i} + 4 \hat{j}\)
A rigid ball of mass M strikes a rigid wall at and gets reflected without loss of speed, as shown in the figure. The value of the impulse imparted by the wall on the ball will be:
1. | Mv | 2. | 2Mv |
3. | Mv/2 | 4. | Mv/3 |