Work Done by a Force

Johnny and his sister Jane race up a hill. Johnny weighs twice as much as Jane and takes twice the time as long as Jane to reach the top. Compared to Jane:

A block of mass $50 \mathrm{kg}$ just slides over a distance of $1 \mathrm{m}$. If the coefficient of friction between their surfaces is $0.2$, the work done against friction is

A cubical vessel of height $1 \mathrm{m}$ is full of water. What is the amount of work done in pumping water out of the vessel?

[Take $g=10 {\mathrm{ms}}^{-2}$]

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

A block of mass $50 \mathrm{kg}$ just slides over a distance of $1 \mathrm{m}$. If the coefficient of friction between their surfaces is $0.2$, the work done against friction is

A cubical vessel of height $1 \mathrm{m}$ is full of water. What is the amount of work done in pumping water out of the vessel?

[Take $g=10 {\mathrm{ms}}^{-2}$]

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

A particle is moving in a force field given $F=y^{2 }\widehat{\mathrm{i}}-x^{2 }\widehat{\mathrm{j}}$ . Starting from A, the particle has to reach C either along ABC or ADC. Let the work done along the two paths be W₁ and W₂ respectively. Then, (W₁, W₂) are

A force $F$ acting on an object varies with distance x as shown in the figure. The work done by the force in moving the object from $x=0$ to $x=20 \mathrm{m}$ is

The work done by a body against friction always results in

A time dependent force $F=6t$ acts on a particle of mass $1 \mathrm{kg}$. If the particle starts from the rest, the work done by the force during the first $1 \sec$ will be:

Suresh slowly pulls a vessel of water from a well of depth $h=20 \mathrm{m}.$ How much work is done (in $\mathrm{kJ}$) by Suresh?
Given that, mass of the uniform rope$\left(m\right)=200 \mathrm{g}$ and vessel of water$\left(M\right)=19.9 \mathrm{kg}$.

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.

A particle is moved along a path $ABCDEFA,$ as shown in figure, in presence of a force $\overrightarrow{F}=\left(\alpha y\hat{\mathrm{i}}+2\alpha x\hat{ȷ}\right) \mathrm{N}$, Where $x$ and $y$ are in meter and $\alpha =-1 \mathrm{N} {\mathrm{m}}^{-1}$. The work done on the particle by this force $\overrightarrow{F}$ $\left(\text{in} \mathrm{J}\right)$ is $\frac{p}{100}$, find $p$.

A man spends $6.4 \mathrm{k} \mathrm{J}$ energy in displacing a body by$64 \mathrm{m}$ in the direction in which he applies force, in $2.5 \mathrm{s}$. The force applied and the power spent (in hp) by the man respectively are:

An electric motor of power $100 \mathrm{W}$ is used to drive the stirrer in a water bath. If $50\%$ of the energy supplied to the motor is spent in stirring the water, calculate the work done (in joules) on water in one minute.

The power of heart which beats $72$ times in a minute is $1.2 \mathrm{kW}$. Calculate the work done (in joules) by the heart for each heartbeat.