NEET UG PHYSICS MCQ: WORK-ENERGY-POWER

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A boy carrying a box on his head is walking on a level road from one place to another on a straight road is doing no work. The statement is

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Correct option: B

correct

The correct answer is B. The work done is zero because the force exerted by the boy is vertical, while the displacement is horizontal, resulting in a 90-degree angle between them, and

W = Fd\cos{\theta}

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{A}

ball is dropped on the ground from a height of

2 {~m}

. If the coefficient of restitution is 0.6 , the height to which the ball will rebound is A running man has the same kinetic energy as that of a boy of half his mass. The man speed up by

2\mathrm{\;m}{\mathrm{s}^{ - 1}}

and the boy changes his speed by

x = \mathrm{m}{\mathrm{s}^{ - 1}}

, so that the kinetic energies of the boy and the man are again equal. Then x in

\mathrm{m}{\mathrm{s}^{ - 1}}

is A force

\mathrm{\vec F} = - K\left( {y\hat i + x\hat j} \right)

(where K is a positive constant) acts on a particle moving in the x-y plane. Starting from the origin, the particle is taken along the positive x-axis to the point (a,0) and then parallel to the y-axis to the (a,a). The total work done by the force

\mathrm{\vec F}

on the particle is A motor is used to deliver water at a certain rate from a given pipe. To obtain 3 times water from same pipe in same time, by what factor should power of the motor be increased. A body projected vertically from the earth reaches a height equal to earth’s radius before returning to the earth. The power exerted by the gravitational force is greatest The speed limit of a car over a roadways bridge in the form of a vertical arc is

9.8\;\mathrm{m}{\mathrm{s}^{ - 1}}

. The diameter of the are is