List of top Physics Questions on Work Power and Energy

A force of $250\text{ N}$ is required to lift a mass of $75\text{ kg}$ through a pulley system. In order to lift this mass through $3\text{ m}$, the rope has to be pulled through $12\text{ m}$. The efficiency of the system is:

The power of a crane, which lifts a mass of 1000 kg to a height of 20 m in 10 s is: (g = 9.8 m/s²)

A \(5\,\text{kg}\) block pushed by \(100\,\text{N}\) over \(10\,\text{m}\) on a plane. If the coefficient of friction between the block and plane is \(0.2\), then the final kinetic energy of the block is _ _ _ (\(g=10\,\text{m s}^{-2}\)):

A force \(F=4x\) is applied to move an object from \(x=0\) to \(x=2\,m\), then the work done is:

A block of mass 3 kg is moving down with constant velocity along a rough inclined plane. The work to be done by an external force in pulling the block along the inclined plane through a height of 50 cm is (Acceleration due to gravity $=10\,ms^{-2}$)

The power \(P\) (in watt) acting on a body of mass \(2\text{ kg}\) is given by \[ 4.5P=8t^2+14t+9 \] where \(t\) is time in second. If the body starts from rest at \(t=0\), then the velocity of the body at time \(t=3\text{ s}\) is

Two forces are acting on a block of mass \(5\,\text{kg}\) as shown in the figure. If the coefficient of kinetic friction between the block and the surface is \(0.25\), then the net work done in accelerating the block for \(15\) seconds is (Acceleration due to gravity \(=10\,\text{ms}^{-2}\)):

A body is moving in a straight line with constant power. The distance moved by the body in time t is proportional to:

If force, $F=kv^{n}$ (k is constant) and power delivered is independent of velocity 'v', then n equals to:

A spherical ball of mass 2 kg falls from a height of 10 m and is brought to rest after penetrating 10 cm into sand. The average force exerted by sand on the ball is _______ N.}

A body of mass 2 kg is thrown vertically upwards from the ground level with kinetic energy of 240 J. The kinetic energy of the body will become half at a height of (\( g=10 \text{ ms}^{-2} \)):

A body of mass 2 kg is thrown vertically upwards from the ground level with kinetic energy of 240 J. The kinetic energy of the body will become half at a height of (\( g=10 \text{ ms}^{-2} \)):

An object is sliding from the top of the smooth inclined plane of height \( h \) from rest and it just completes a vertical circle of diameter 20 cm. Then the minimum height \( h \) of smooth inclined plane is:

A body of mass 3 kg is under a force, which causes a displacement in it given by $S = \frac{t^3}{3}$ (in m). Find the work done by the force in first 2 seconds:

A block of mass m = 0.1 kg is released from a height of 4 m on a curved smooth surface. On the horizontal surface, path AB is smooth and path BC is rough with a coefficient of friction, $\mu = 0.1$. If the impact of the block with the vertical wall at C is perfectly elastic, the total distance covered by the block on the horizontal surface before coming to rest will be:

A ball of mass 100 g is projected with velocity 20 $ms^{-1}$ at $60^{\circ}$ with horizontal. The decrease in kinetic energy of the ball during its entire upward journey is:

A 15 W machine used $(3i + 5j + 6k)$ N force for 6 seconds to lift a body through a distance of X m along x - axis. The value of X is:

A mass of 1 kg is kept on a inclined plane with $30^\circ$ inclination with respect to horizontal plane and it is at rest initially. Then the whole assembly is moved up with constant velocity of 4 m/s. The work done by the frictional force in time 2 s is \dots J. (Take $g = 10 \text{ m/s}^2$)

The velocity at which \(6\,\text{kg}\) mass (shown in figure) strikes the ground when it is released from a height of \(6\,\text{m}\) above the ground is _____ m/s. Assume pulley is massless and string is light and inextensible. (Take \(g=10\,\text{m/s}^2\)).

A body of mass \(1\,\text{kg}\) moves along a straight line with a velocity \(v=2x^2\). The work done by the body during displacement from \(x=0\) to \(x=5\,\text{m}\) is _____ J.

A body of mass 2 kg begins to move under the influence of time dependent force \(\vec{F} = (2t \hat{i} + 6t^2 \hat{j})\) N, where \(\hat{i}\) and \(\hat{j}\) are unit vectors along x and y-axis respectively. The power produced by the force at \(t = 2\) s is ______ W.

An engine pumps water continuously through a hose pipe. If the water leaves the pipe with velocity $v$ and $m$ is the mass per unit length of the water in the pipe, then the rate at which kinetic energy is imparted to the water is:

The power generated by a turbine operated by the fall of water from a height of 100 m at the rate of $24\text{ kg s}^{-1}$ is 21 kW. The percentage loss in power is

A non-conservative force is one for which