V K Sally and R Goel Solutions for Chapter: Work and Energy, Exercise 4: EXERCISE

An object is thrown up at angle $Q,$ from point $A,$ reaches to the point $B$ after rising through the height h as shown in diagram. The work done by the force of gravity is

A displacement of $10 \mathrm{m}$ is caused in a body in the following different ways. In which case maximum work is done?

No work is done when an object moves

A toy car is taken from one point to another point on a rough surface in different directions. Study the statements given below and select the correct answer:

(P) Work done from one point to another point does not depend on the direction in which the body is moved and work done is same irrespective of the nature of path.

(Q) The net work done against the force of friction depends upon the distance moved by the body.

Select the following statements and select the correct answer:
(P) A stone thrown vertically upward returns back to thrower in $2 \mathrm{s}$. The net work done by the gravitation force acting on the stone is zero.
(Q) Gravitational force cannot be conserved.

$1$ Joule in terms of mass, length and time is

A force of $7 \mathrm{N}$ acts on an object through a distance of $8 \mathrm{m}$ in its own direction. The work done is

A boy pulls up a bucket of water from a well $80 \text{m}$ deep. If the mass of the bucket along with water is $20 \mathrm{kg}$, the amount of work done by the boy is : $\left(\mathrm{g}=10 \mathrm{m} {\mathrm{s}}^{-2}\right)$