Work

Q.

An ideal gas heat engine operates in a Carnots cycle between ${227}^{\circ }C$ and ${127}^{\circ }C$. It absorbs $6\times {10}^4$J at high temperature. The amount of heat converted into work is ....

1. 

2. 

3. 

4. 

Q. The energy of a system as a function of time t is given as E(t) =A^2 exp(-at), where a=0.2 s^-1. The measurement of A has an error of 1.25%. If theerror in the measurement of time is 1.50%, the percentage error in thevalue of E(t) at t5 sec is

Q. A thermodynamic system is taken from an original state to an intermediate state by the linear process shown in Its volume is then reduced to the original value from E to F by an isobaric process. Calculate the total work done by the gas from D to E to F

Q.

A particle of mass m moves on a straight line with its velocity varying with the distance travelled according to the equation v = a$\sqrt{x}$, where 'a' is a constant.Find the total work done by all the forces during a displacement from x = 0 to x = d.

1. 

2. 

3. 

4. none of these

Q. A block whose mass is 500g is fastened to a spring . The spring has spring constant 100N/m . The block is pulled to a distance of x=10 cm from its equilibrium position state of x=0 from rest at t=0. What is kinetic energy of block at x=5cm?

Q.

If the unit of force and length each be increased by four times, then the unit of energy is increased by

1. 16 times

2. 8 times

3. 2 times

4. 4 times

Q. A string tied on a roof can bear a maximum tension of 50 kg weight.the minimum acceleration that can be required by a man of 98 kg to decide will be (take g=9.8). Assume that there is no friction between the rope and the man that is all surfaces are frictionless.

Q.

During the adiabatic expansion of 2 moles of a gas, the internal energy of the gas is found to decrease by 2 joules, the work done during the process on the gas will be equal to

1. 1 J

2. -1 J

3. 2 J

4. -2 J

Q. An ideal gas undergoes a polytropic process given by equation PV^n=cons†an t. If molar heat capacity of gas during this process is arithmetic mean of its molar heat capacity at cons†an t pressure and cons†an t volume, then value of n is

Q. A chain of mass 2Kg is placed on a smooth table with 1/4th of its length hanging over the edge. if the length of chain is 4m then the work done in pulling the hanging portion of the chain back to the surface of the table is (1)5J (2)2.5J (3)2J (4)4J

Q.

A metre stick , of mass 400 g, is pivoted at one end displaced through an angle ${60}^{\circ }$ . The increase in its potential energy is

1. 1 J

2. 10 J

3. 1000 J

4. 100 J

Q.

A gas expands under constant pressure P from volume $V_1$ to $V_2$. The work done by the gas is

1. 

2. 

3. 

4. 

Q. A solid cylinder and a solid sphere of same mass and radius roll without slipping on a rough inclined planeThe force of friction is(1) Same for both the bodies(3) More for sphereY2) More for cylinden(4) Double for sphere than for cylinderh

Q. A force F=Kx^2 acts on a particle at an angle of 60^0 with the x- axis .the work done in displacing the particle from x_1 to x_2 will b

Q. if force is on 60 degree angle and displacement is horizontal then what will be the work done by body ?

Q. 27.Spring of unstretched length L has a mass M with one end fixed to a rigid support.Assuming spring to be made of a uniform wire , the kinetic energy possessed by it if its free end is pulled with uniform velocity V is .

Q. A worker pushes a wheelbarrow with a horizontal force of 50 N on level ground over a distance of 5.0 m. If a friction force of 43 N acts on the wheelbarrow in a direction opposite that of the worker, what work is done on the wheelbarrow by the worker

Q. 91. A boy is sitting on the horizontal platform of a joy wheel at a distance of 5 m from the centre. The wheel begins to rotate and when the angular speed exceeds 1 rad/s , the boy just slips. The coefficient of friction between the boy and the wheel is ?

Q. The gravitational unit of work (kg-m) is equal to

Q. 37. A solid cylinder rolls down an inclined plane .Its mass is 2kg and radius 0.1m . If the height of the inclined plane is 4m what is the rotational kinetic energy when it reaches the foot of the plane?

Q. Two bulbs A and B of same volume contain an ideal gas at temperature T and pressure P. When the temperature of the bulb B is doubled and that of A remains unchanged, the pressure of the gas will be (Neglect the volume of the tube connecting the two bulbs) (1) 2P (2) 4/3 P (3) 1.5 P (4) 1.2 P

Q. when a beam is bent (1) only extensional strain is produced (2) only compressional strain is produced (3) both extensional as well as compressional strain is produced (4) compressional as well as extensional strain is never produced

Q. 66.a body of mass 2 kg is rotating in a vertical circle of radius 4 metre. the difference in its kinetic energy at the top and bottom of the circle is

Q. a block of mass m is being pulled upon the rough inclined plane by a man delivering cons†an t power P. the coefficient of friction between the block and incline is u. the maximum speed of block during ascent is ?

Q. work done by restoring force in a string within elastic limit is -10J. Maximum amount of heat produced in the string is?

Q. A particle moves under the effect of a force F=3x, where x is the displacement \lbrack force is in N and displacement is in m\rbrack.The particle is displaced from x=0 to x=4m.The net work done by force in this process i

Q. a block whose mass is 2kg is fastened to a spring whose spring cons†an t is 100. It is pulled to a dis†an ce x=0.1m from its equilibrium position at x= 0 on a frictionless surface from rest at t= 0 .calculate the kinetic energy of the block when it is 0.05m away from the mean positio mean position.

Q.

For a particle executing simple harmonic motion, which of the following statements is not correct

[MP PMT 1997; AIIMS 1999; Kerala PMT 2005]

1. The restoring force of always directed towards a fixed point

2. The restoring force is maximum at the extreme positions

3. The total energy of the particle always remains the same

4. The acceleration of the particle is maximum at the equilibrium position

Q. average energy in a time period of a SHM i

Q. A body is launched up an inclined plane with inclination Alpha to horizontal. It is observed that the time of ascent is half of the time of descent along length of incline. The coefficient of friction between the body and the incline is xtanalpha find the value of x