Chapter Test: Work. Power & Energy - 1 - JEE MCQ

By burning 1 g of coal, the energy produced is 2 kcal. Then for 1 kWh, the quantity of coal so required will be nearly -

A uniform chain of length L and mass M is lying on a smooth table and one-third of its length is hanging vertically down over the edge of the table. If g is acceleration due to gravity, the work required to pull the hanging part on to the table is –

Water from a stream is falling on the blades of a turbine at the rate of 100 kg/sec. If the height of the stream is 100 m, then the power delivered to the turbine is -

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 -

The relationship between the force F and position x of a body is as shown in figure. The work done in displacing the body from x = 1m to x = 5m will be-

Assertion : When a spring is elongated work done by spring is negative but when it compressed work done by spring is positive.

Reason : Work done by spring is path independent.

A particle moves in a straight line with its retardation proportional to its displacement 'x'. Change in kinetic energy is proportional to –

A particle moves along the x-axis from x = 0 to x = 5m under the influence of a force given by F = 7 – 2x + 3x². The work done in the process is-

A block of mass m slides along the track with kinetic friction μ. A man pulls the block through a rope which makes an angle θ with the horizontal as shown in the figure. The block moves with constant speed V. Power delivered by the man 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

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 attached to a massless spring is performing oscillatory motion of amplitude 'A' on a frictionless horizontal plane. If half of the mass of the block breaks off when it is passing through its equilibrium point, the amplitude of oscillation for the remaining system become fA. The value of f 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 The value of x is _______. (in integers)

In a spring gun having spring constant 100 N/m, a small ball 'B' of mass 100 g is put in its barrel (as shown in figure) by compressing the spring through 0.05 m. There should be a box placed at a distance 'd' on the ground so that the ball falls in it. If the ball leaves the gun horizontally at a height of 2 m above the ground, the value of d is _______________ m.
(g = 10 m/s²) (in integers)