According to the work-energy theorem, the change in kinetic energy of a body is equal to work done by:
1. Non-conservative force on the particle
2. Conservative force on the particle
3. External force on the particle
4. All the forces on the particle
A block is carried slowly up an inclined plane. If is work done by the friction, is work done by the reaction force, is work done by the gravitational force and is the work done by an external force, then choose the correct relation(s):
1.
2. = 0
3.
4. All of these
The position of a particle \((x)\) varies with time \((t)\) as \(x = (t - 2)^2\), where \(x\) is in meters and \(t\) is in seconds. Calculate the work done during \(t=0\) to \(t=4\) s if the mass of the particle is \(100~\text{g}.\)
1. \(0.4\) J
2. \(0.2\) J
3. \(0.8\) J
4. zero
A particle of mass m is moving in a circular path with a speed v = kt, where k is constant and t is time. The instantaneous power delivered to the particle is:
1. | Zero | 2. | mkt |
3. | 4. |
A position-dependent force; \(F=6+8x-3x^2\) N acts on a small body of mass \(3\) kg, displacing it from \(x=0\) to \(x=2\) m. The work done in joule is:
1. \(20\)
2. \(40\)
3. \(10\)
4. \(12\)
A car of mass 100 kg and traveling at 20 m/s collides with a truck weighing 1 tonne traveling at 9 km/h in the same direction. The car bounces back at a speed of 5 m/s. The speed of the truck after the impact will be:
1. 11.5 m/s
2. 5 m/s
3. 18 m/s
4. 12 m/s
Which of the following remains unchanged (for the system) during an inelastic collision?
1. | Mechanical energy | 2. | Kinetic energy |
3. | Momentum | 4. | All of the above. |
An object of mass m = 1.5 kg is acted upon by the force as shown in the figure that varies with the position of the object as shown. If the object starts from rest at a point x = 0, then what is its speed at x = 50 m?
1. 20 m/s
2. 25 m/s
3. 15 m/s
4. 17 m/s
The work done by a person in carrying a box of mass 10 kg to a vertical height of 10 m is 4900 J. The mass of the person is:
1. 40 kg
2. 60 kg
3. 50 kg
4. 55 kg
The principle of conservation of energy implies that:
1. the total mechanical energy is conserved.
2. the total kinetic energy is conserved.
3. the total potential energy is conserved.
4. the sum of all types of energies is conserved.