Work, Power and Energy Questions

The work done on a particle of mass m by a force, (K being a constant of appropriate dimensions), when the particle is taken from the point (a, 0) to the point (0, a) along a circular path of radius a...

Three blocks with masses m, 2m and 3m are connected by strings,as shown in the figure. After an upward force F is applied on block m, the masses move upward at constant speed v. What is the net force ...

Two pith balls carrying equal charges are suspended from a common point by strings of equal length, the equilibrium separation between them is r. Now the strings are rigidly clamped at half the height...

A uniform force of newton acts on a particle of mass 2 kg. Hence the particle is displaced from position meter to position meter. The work done by the force on the particle is :-...

A force , (where k is a positve constant) acts on a particle moving in the x-y plane. String from the origin, the particle is taking along the positve x-axis to the point (a, o) and parallel to the y-...

When a rubber-band is stretched by a distance x, it exerts a restoring force of magnitude F = ax + bx2 where a and b are constants. The work done in stretching the unstretched rubber-band by L is :...

The upper half of an inclined plane with inclination φ is perfectly smooth while the lower half is rough. A body starting from rest at the top will again come to rest at the bottom if the coeffic...

A metal surface is illuminated by light of two different wavelengths 248 nm and 310 nm. The maximum speeds of the photoelectrons corresponding to these wavelengths are u1 and u2, respectively. If the ...

A tennis ball is dropped on a horizontal smooth surface. It bounces back to its original position after hitting the surface. The force on the ball during the collision is proportional to the length of...

A mass of 20 kg moving with a speed of 10 m/s collides with another stationary mass of 5 kg. As a result of the collision, the two masses stick together. The kinetic energy of the composite mass will ...

Under the action of a force, a 2 kg body moves such that its position x as a function of time is given by x = , where x is in meters and t is in sec. The work done by the force in the first two second...

A Carnot engine, having an efficiency of as heat engine, is used as a refrigerator. If the work done on the system is 10 J, the amount of energy absorbed from the reservoir at lower temperature is :-...

A mass m moves in a circle on a smooth horizontal plane with velocity v0 at a radius R0. The mass is attached to a string which passes through a smooth hole in the plane as shown. The tension in the s...

A resitance ′R′ draws power ′P′ when connected to an AC source. If an inductance is now placed in series with the resistance, such that the impedance of the circuit becomes &#8...

Two similar springs P and Q have spring constants KP and KQ, such that KP > KQ. The are stretched, first by the same amount (case a,) then by the same force (case b). The work done by the springs W...

A particle of mass m is driven by a machine that delivers a constant power k watts. If the particle starts from rest the force on the particle at time t is :

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times. Assume that the potential energy lost each time he lowers the mass is dissipated. How much fat will...

A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of resulting system :-

Preeti reached the metro station and found that the escalator was not working. She walked up the stationary escalator in time t1. On other days, if she remains stationary on the moving escalator, then...

A spherical black body with a radius of 12 cm radiates 450 watt power at 500 K. If the radius were halved and the temperature doubled, the power radiated in watt would be :-