Work Energy And Power - Physics PYQ

What is the shape of the graph between speed and kinetic energy of a body?

A quarter horse power motor runs at a speed of 600 rpm. Assuming 60% efficiency, the work done by the motor in one rotation is

A body of mass 8 kg, under the action of a force, is displaced according to the equation, \(s=\frac{t^2}{4}\) m, where t is the time. Find the work done by the force in the first 4 s.

An engine develops 20 kW of power. How much time will it take to lift a mass of 200 kg to a height of 40 m? (g = 10 ms\(^{-2}\) )

Water is falling on the blades of a turbine from a height of \(25 \mathrm{~m}\) and \(3 \times 10^3 \mathrm{~kg}\) of water pours on the blade per minute. If the whole of energy is transferred to the turbine, then power delivered is

Two bodies having kinetic energy in the ratio 4 : 1, are moving with same linear velocity. The ratio of their masses is

The range of a projectile is 100 m. Its kinetic energy will be maximum after covering a distance of

A uniform chain has a mass m and length \(l\). It is held on a frictionless table with one-sixth of its length hanging over the edge. The work done in just pulling the hanging part back on the table is

A rifle bullet loses \(\left(\frac{1}{25}\right)\)th of its velocity in passing through a plank. The least number of such planks required just to stop the bullet is

When a force F = 17 \(-\) 2x + 6x\(^2\)N acts on a body of mass 2 kg and displaces it from x = 0 m to x = 8 m, the work done is

A ball of mass 300 g is dropped from a height 10 m above a sandy ground. On reaching the ground, it penetrates through a distance 1.5 m in sand and finally stops. The average resistance offered by the sand to oppose the motion is (acceleration due to gravity \(=10 \mathrm{~ms}^{-2}\))

A bead of mass 400 g is moving along a straight line under a force that delivers a constant power 1.2 W to the bead. If the bead is initially at rest, the speed it attains after 6 s in \(\mathrm{ms}^{-1}\)

A mass of 1 kg falls from a height of 1 m and lands on a massless platform supported by a spring having spring constant \(15 \mathrm{~Nm}^{-1}\) as shown in the figure. The maximum compression of the spring is (acceleration due to gravity \(=10 \mathrm{~ms}^{-2}\))

A block of mass 50 kg is pulled with a constant speed of \(4 \mathrm{~ms}^{-1}\) across a horizontal floor by an applied force of 500 N directed \(30^{\circ}\) above the horizontal. The rate at which the force does work on the block in watt is

A small disc of mass \(m\) slides down with initial velocity zero from the top \((A)\) of a smooth hill of height \(H\) having a horizontal portion \((BC)\) as shown in the figure. If the height of the horizontal portion of the hill is \(h\), then the maximum horizontal distance covered by the disc from the point \(D\) is

A $4 \mathrm{~kg}$ mass is suspended as shown in figure. All pulleys are frictionless and spring constant $k$ is $8 \times 10^3 \mathrm{Nm}^{-1}$. The extension in spring is $\left(g=10 \mathrm{~ms}^{-2}\right)$