Work

When a force is applied on a moving body, its motion is retarded. Then the work done is

Deduce work energy theorem for constant force.

Explain work.

A force of $\overrightarrow{F}=(2\hat{i}+3\hat{j}+4\hat{k}) N$ is applied on a particle displacing it by a distance $\overrightarrow{\mathrm{d}}=(3\hat{\mathrm{i}}-2\hat{\mathrm{j}}+\hat{\mathrm{k}})\mathrm{m}$. Calculate the work done by the force.

When a force is applied on a moving body, its motion is retarded. Then the work done is

The amount of work done by the centripetal force when the earth revolves around the sun is _____.

(Choose from zero/non-zero)

Force of $4 \mathrm{N}$ is applied on a body of mass $20 \mathrm{kg}$. Find the work done in Joules in $3$rd second.

Describe the properties of work done.

A gardener pulls a lawn roller along the ground through a distance of $20 \mathrm{m}.$ If he applies a force of $20 \mathrm{kg} \mathrm{wt}$ in a direction inclined at $60°$ to the ground, find the work done by him. (Take $g=10 \mathrm{m} {\mathrm{s}}^{-2}$):

If this lift is moving downward with constant velocity $20 \mathrm{m} {\mathrm{s}}^{-1},$ find work done by tension in $2 \sec$:-

A body of mass $10 \mathrm{kg}$ initially at rest is displaced by $5 \mathrm{m}$ against the of force $100 \mathrm{N}$ acting in the direction opposite to the direction of displacement of the body. What will be the work done by the force on the body?

A body of mass $5 \mathrm{kg}$ initially at rest is displaced by $2 \mathrm{m}$ under the application of force $90 \mathrm{N}$ acting at an angle $\theta$ to the motion of the body. What will be the value of $\theta$ such that the work done on the body by the force will be minimum.

Work will said to be done if the force and displacement are

A body constrained to move along y-axis is subjected to a constant force $\overrightarrow{F}=-\widehat{i}+2\widehat{j}+3\widehat{k} \mathrm{N}.$ The work done by this force in moving the body a distance of $4 \mathrm{m}$ along $Y$-axis is _____ $\mathrm{J}$.

A man carrying a load on his head and moving along a horizontal road does _____ work.
(Choose from: zero/positive/negative)

Force and displacement are inclined to each other at an angle of $120°$. Will the work done be positive or negative?

An adult weighing $600\mathrm{ }\mathrm{N}$ raises the centre of gravity of his body by $0.25 \mathrm{m}$ while taking each step of $1 \mathrm{m}$ length in jogging. If he jogs for $6 \mathrm{km}$, the energy utilised by him in jogging is

The potential energy of a spring when stretched through a distance $x$ is $10\mathrm{ }\mathrm{J}$. What is the amount of work done on the same spring to stretch it through an additional distance $x$?

The work done by a body against friction always results in

Figure shows four situations in which a force is applied to a block. In all four cases, the force has the same magnitude, and the displacement of the block is to the right and of the same magnitude. In which of the following cases, work done by the applied force on the block is zero?

A block of mass $1 \mathrm{kg}$ is pushed up a surface inclined to horizontal at an angle of $30°$ by a force of $10 \mathrm{N}$ parallel to the inclined surface as shown in the figure.
The coefficient of friction between the block and the incline is $0.1.$ If the block is pushed up by $10\mathrm{ }\mathrm{m}$ along the incline, then the work against gravity is (Take $g=10 \mathrm{m} {\mathrm{s}}^{-2}$ )