List of top Physics Questions on Work Power and Energy

A particle is subjected to a force F = 3x$^2$. Calculate the work done in moving with particle from x=0 to x = 2 m.
Three bulbs of power 10 W, 25 W, and 50 W are connected parallel across a voltage source \( V \). What is the effective power of the combination?
If \( \vec{F} \) and \( \vec{S} \) represent force and displacement respectively, then which of the following statements is true:
A body of mass 0.2 kg is falling freely from a height of 180 m from the ground. The ratio of the works done by the gravitational force in the first two seconds and in the next two seconds of motion of the body is
A body of mass 50 g is projected vertically upwards from the ground. If the kinetic energy of the body at a height of 32 m is 100% more than its potential energy, then the height at which the potential energy of the body becomes 60% of its kinetic energy is
A bullet of mass $m$ moving with a velocity $u$ gets embedded in a block of mass $M$ initially at rest. If $\mu$ is the coefficient of friction between the block and the ground, then the displacement of the block due to the impact is:
A vertical spring of spring constant \(24Nm^{-1}\) is fixed on a table. A ball of mass \(0.5\,kg\) at a height \(2\,m\) above the free upper end of the spring falls vertically on the spring so that the spring is compressed by a distance of \(50\,cm\). The net work done in the process is:
An ideal inductor is connected across a capacitor. Oscillations of energy \(K\) are set up in the circuit. The capacitor plates are slowly drawn apart such that the frequency of oscillations is quadrupled. The work done in the process is
A body of mass 10 kg is moving with a velocity of 20 m/s. What is the kinetic energy of the body?
A bomb of mass 12 kg at rest explodes into two pieces of masses 4 kg and 8 kg. If the velocity of 8 kg mass is \( 6\,{ms}^{-1} \), then the kinetic energy of 4 kg mass is
A body is dropped freely from a height of 8 m from the ground. If the coefficient of restitution between the body and the ground is 0.5, then the maximum height reached by the body after second impact with the ground is
The work done to take a body of mass 100 kg to the top of a building of height 20 m is (Acceleration due to gravity = 10 m s\textsuperscript{-2})
A body is moving along a straight line under the influence of a constant power source. If the relation between the displacement (s) of the body and time (t) is \(s \propto t^x\), then \(x =\)
Which one of the following forces cannot be expressed in terms of potential energy?
A block of mass 1 kg, moving along x with speed \( v_i = 10 \) m/s enters a rough region ranging from \( x = 0.1 \) m to \( x = 1.9 \) m. The retarding force acting on the block in this range is \( F_r = -kx \) N, with \( k = 10 \) N/m. Then the final speed of the block as it crosses this rough region is
A block of mass 25 kg is pulled along a horizontal surface by a force at an angle $ 45^\circ $ with the horizontal. The friction coefficient between the block and the surface is 0.25. The displacement of 5 m of the block is:
Energy is not carried by
A spring has a spring constant \( k \). When the spring is stretched through 1 cm, the potential energy is \( U \). What will be the potential energy if it is stretched by 4 cm?
If a force of \( (6x^2 - 4x) \, \text{N} \) acts on a body of mass 10 kg, then the work to be done by the force in displacing the body from \( x = 2 \, \text{m} \) to \( x = 4 \, \text{m} \) is
A force \( F \) is applied on a body of mass \( m \) so that the body starts moving from rest. The power delivered by the force at time \( t \) is proportional to:
A train of mass \(10^6 \, \text{kg}\) is moving at a constant speed of \(108 \, \text{km/h}\). If the frictional force acting on it is \(0.5 \, \text{N per 100 kg}\), then the power of the train is
A simple pendulum of length 1m is released from horizontal position. If 20% its initial energy is lost due to air resistance in reaching the mean position, then the speed of the bob of the pendulum at mean position is (Acceleration due to gravity = 10 m s\textsuperscript{-2})
A force of 10 N acts on a 2 kg object initially at rest, moving it 8 m along a straight line. What is the work done by the force? Assume the force is parallel to the displacement.
If $P$ is the pressure at which the heart is pumping the blood and the volume of blood pumped per second is $V$, then the power of the heart is given by
A particle of mass m moves on a straight line with its velocity increasing with distance according to the equation \( v = \alpha \sqrt{x} \), where \(\alpha\) is a constant. The total work done by all the forces applied on the particle during its displacement from \( x = 0 \) to \( x = d \), will be: