Physics Unit Test: Work, Power & Energy(June 25) - JEE MCQ

A body at rest is moved along a horizontal straight line by a machine delivering a constant power. The distance moved by the body in time 't' is proportional to

Given below is the plot of a potential energy function U(x) for a system, in which a particle is in one dimensional motion, while a conservative force F(x) acts on it. Suppose that E_mech = 8 J, the incorrect statement for this system is:

A particle of mass 1 kg is hanging from a spring of force constant 100 Nm^-1. The mass is pulled slightly downward and released, so that it executes free simple harmonic motion with time period T. The time when the kinetic energy and potential energy of the system will become equal is T/x. The value of x is _______. (in integers)

A free electron of 2.6 eV energy collides with a H⁺ ion. This results in the formation of a hydrogen atom in the first excited state and a photon is released. Find the frequency of the emitted photon (h = 6.6 × 10^-34 J s).

A body of mass M at rest explodes into three pieces, in the ratio of masses 1 : 1 : 2. Two smaller pieces fly off perpendicular to each other with velocities of 30 ms^-1 and 40 ms^-1 respectively. The velocity of the third piece will be:

A particle of mass 500 gm is moving in a straight line with velocity v = b x^5/2. The work done by the net force during its displacement from x = 0 to x = 4 m is: (Take b = 0.25 m^-3/2 s^-1)

A body of mass 0.5 kg travels on a straight line path with velocity v = (3x² + 4) m/s. The net work done by the force during its displacement from x = 0 to x = 2 m is:

As per the given figure, two blocks each of mass 250 g are connected to a spring of spring constant 2 Nm^-1. If both are given velocity v in opposite directions, then maximum elongation of the spring is:

Two cylindrical vessels of equal cross-sectional area 16 cm² contain water up to heights 100 cm and 150 cm, respectively. The vessels are interconnected so that the water levels in them become equal. The work done by the force of gravity during the process is: [Take density of water = 10³ kg/m³ and g = 10 ms^-2]

A block of mass 'm' (as shown in figure) moving with kinetic energy E compresses a spring through a distance 25 cm when its speed is halved. The value of spring constant of used spring will be nE Nm^-1 for n = _____________. (in integers)

A stone of mass m tied to a string is being whirled in a vertical circle with a uniform speed. The tension in the string is

A particle experiences a variable force = in a horizontal x-y plane. Assume distance in meters and force in newton. If the particle moves from point (1, 2) to point (2, 3) in the x-y plane; then kinetic energy changes by