Work Done

Q.

A spherical bubble inside water has radius$\mathrm{R}$. Take the pressure inside the bubble and the water pressure to be${\mathrm{p}}_0$. The bubble now gets compressed radially in an adiabatic manner so that its radius becomes $(\mathrm{R}-\mathrm{a})$. For $𝑎<<\mathrm{R}$ the magnitude of the work done in the process is given by $\left(4{\mathrm{\pi P}}_0{\mathrm{R}}^2\mathrm{a}\right)\mathrm{X}$, where $\mathrm{X}$ is a constant and$\mathrm{\gamma }=𝐶𝑝⁄𝐶𝑉=41⁄30$. The value of$\mathrm{X}$ is________.

Q. A rod of length 1.0 m and mass 0.5 kg fixed atone end is initially hanging vertical. The otherend is now raised until it makes an angle 60^° with the vertical. The work required to be donefor this, is(a) 1.2 J(c) 2.4J(b) 1.8J(d) 3.0 J

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

Q. The particle moves along x axis under the action of a position dependent force F=(5x2-2x)N work done by forces on the particle when it moves from origin to x =3m is?

Q. the work done by an applied variable force F=x+x^3 from x=0 m to x=2m where x is displacement is

Q. A stone of mass 20 g falling from height of 2 km hits the ground with a speed of 200 ms–1. The work done by the gravitational force is Options: 100 J 200 J 300J 400J

Q. A drop of mass 2.0 g falls from a cliff of height 1.0 km. It hits the ground with a speed of 50.0 m/s. The work done by resistive force is ? (1) -10 J (2) -12.50 J (3) -15.5 J (4) -17.50 J

Q. There is an elastic ball anda rigid wall. Ball is throwntowards the wall. The work done by the normal reaction exerted by the wall on the ball is -

Q. Find the work done if a particle moves from position r1 to a position r2 under the effect of force, F

Q. A body of mass 15 kg is raised from certain depth. If the work done in raising it by 10m is 1620J, its velocity at this position is

Q. a constant force f= -i+2j+3k N is acting on a particle. What will be the total work done by this force first in moving the particle 4m along z axis ?

Q. A uniform chain of length 12 cm and mass 2 kg 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 [Take g = 10 m/s^2]

Q. A metre scale of mass 50 g is lying on ahorizontal table. What is the work donein making it stand vertical on one end?-2

Q. A container with a mass of 5 kg is lifted to a height of 8 m. Work done by the gravitational force is equal to

1. 40 J
2. -40 J
3. 400 J
4. -400 J

Q.

An ideal gas expands isothermally from a volume $V_1$ to $V_2$ to and then compressed to original volume $V_1$ adiabatically. Initial pressure is $P_1$ and final pressure is $P_3$. The total work done is W. Then

1. 

2. 

3. 

4. 

Q. An ideal gas is taken from state $A$ to the state $B$, as shown in the $P-V$ diagram. The work done in the process is

1. $(P_A-P_B)\times (V_B-V_A)$
2. $\frac{1}{2}(P_B-P_A)\times (V_B+V_A)$
3. $\frac{1}{2}(P_B-P_A)\times (V_B-V_A)$
4. $\frac{1}{2}(P_B+P_A)\times (V_B-V_A)$

Q. The stress-strain graphs for materials A and B are shown in Fig.
The graphs are drawn to the same scale.
(a) Which of the materials has the greater Young's modulus ?
(b) Which of the two is the stronger material ?

Q. The work done in lifting a body of mass 20kg and specific gravity 3.2 to a height of 8m in water is? (g = 10m/s-2)

Q. An unruly demonstrator lifts a stone of mass 200 g from the ground and throws it at his opponent. At the time of projection, the stone is 150 cm above the ground and has a speed of 3 m/s. Calculate the work done by the demonstrator during the process. If it takes one second for the demonstrator to lift the stone and throw it, what horsepower does he use?

Q. Consider the cyclic process $ABCA$ as shown in the figure, performed on a sample of $2.0$ mole of an ideal gas. A total of $1200\text{J}$ of heat is withdrawn from the sample in the process. Find the magnitude of the work done (in joules) by the gas during the part $BC$. $(R=8.3{\text{JK}}^{-1}{\text{mol}}^{-1})$

1. $2580\text{J}$
2. $3625\text{J}$
3. $4520\text{J}$
4. $1550\text{J}$

Q. A gas expands with temperature according to the relation $V=k{T}^{2/3}$. What is the work done, when the temperature changes by ${30}^{\circ }\text{C}$?

1. $10R$
2. $20R$
3. $30R$
4. $40R$

Q. a uniform chain of mass M and length L is lying on a frictionless table in such a way that its 1/3 part is hanging vertically down. the work done in pulling the chain up the table is: (1) MgL/3 (2) MgL/6 (3) MgL/9 (4) MgL/18

Q. In an isothermal reversible expansion if the volume of $96\text{g}$ of oxygen at ${27}^{\circ }\text{C}$ is increased from $70\text{L}$ of $140\text{L}$, then the work done by the gas will be

1. $300{\text{R log}}_{10}2$
2. $81{\text{R log}}_{e}2$
3. $900{\text{R log}}_{10}2$
4. $2070{\text{R log}}_{10}2$

Q. Work done for the process A$\to$ B shown in the figure is

1. $1\text{J}$
2. $1.5\text{J}$
3. $4.5\text{J}$
4. $0.3\text{J}$

Q. $n$ moles of a gas filled in a container is in thermodynamic equilibrium initially at temperature $T$. If the gas is compressed quasi-statically and isothermally to half of its initial volume, the work done on the gas is :

1. $\frac{nRT}{2}$
2. $-\frac{nRT}{2}$
3. $nRT(\text{ln}2-\frac{1}{2})$
4. $nRT\text{ln}2$

Q. A small block of mass 200 g is kept at the top of a frictionless incline which is 10 m long and 3⋅2 m high. How much work was required (a) to lift the block from the ground and put it an the top, (b) to slide the block up the incline? What will be the speed of the block when it reaches the ground if (c) it falls off the incline and drops vertically to the ground (d) it slides down the incline? Take g = 10 m/s².

Q. A thermodynamic system goes from state (i) $(P,V)$ to $(2P,V)$ and (ii) $(P,V)$ to $(P,2V)$ as shown in the figure. Work done in the two cases is :

1. Zero, Zero
2. Zero, $PV$
3. $PV$, Zero
4. $PV,PV$

Q. Two small bodies of masses 2.00 kg and 4.00 kg are kept at rest at a separation of 2.0 m. Where should a particle of mass 0.10 kg be placed to experience no net gravitational force from these bodies? The particle is placed at this point. What is the gravitational potential energy of the system of three particles with usual reference level?

Q. A block of mass 100 g is moved with a speed of 5⋅0 m/s at the highest point in a closed circular tube of radius 10 cm kept in a vertical plane. The cross-section of the tube is such that the block just fits in it. The block makes several oscillations inside the tube and finally stops at the lowest point. Find the work done by the tube on the block during the process.

Q. $n$ moles of a gas filled in a container is in thermodynamic equilibrium initially at temperature $T$. If the gas is compressed quasi-statically and isothermally to half of its initial volume, the work done on the gas is :

1. $\frac{nRT}{2}$
2. $-\frac{nRT}{2}$
3. $nRT(\text{ln}2-\frac{1}{2})$
4. $nRT\text{ln}2$