All questions of Work, Energy and Power for Class 11 Exam

• a)
  
• b)
  
• c)
  
• d)
  

• a)
  negative
• b)
  positive
• c)
  zero
• d)
  infinity

• a)
  
• b)
  
• c)
  
• d)
  

• a)
  4 sec
• b)
  10 sec
• c)
  5 sec
• d)
  8 sec

A body dropped from height H reaches the ground with a speed of 

• a)
  mgh
• b)
  -0.28mgH
• c)
  2gh
• d)
  0.5gh

• a)
  [T²]
• b)
  [T¹]
• c)
  [T^-1]
• d)
  [T^-2]

• a)
  A
• b)
  B
• c)
  Both A and B have developed equal power but B has more energy
• d)
  Both A and B have developed equal power but A has more energy

• a)
  11:12
• b)
  9:11
• c)
  12:11
• d)
  11:9

• a)
  225W
• b)
  15kW
• c)
  9kW
• d)
  900 W

• a)
  Power
• b)
  Torque
• c)
  Centrifugal Force
• d)
  Acceleration

• a)
  1:2
• b)
  4:1
• c)
  1:√2
• d)
  1:4

• a)
  55 %
• b)
  20 %
• c)
  44 %
• d)
  60 %

• a)
  Mgh
• b)
  -Mgh
• c)
  0
• d)
  Mg

• a)
  5000 J
• b)
  900 J
• c)
  9000 J
• d)
  500 J

 A body moves under a force such that momentum of the body at any instant . What is the rate of work done by the force?

• a)
  
• b)
  
• c)
  
• d)
  zero

• a)
  36.5W
• b)
  3.65W
• c)
  365W
• d)
  0.365W

• a)
  kx
• b)
  -kx
• c)
  
• d)
  

• a)
  30,900 J
• b)
  29,678 J
• c)
  39,200 J
• d)
  25,000 J

• a)
  Force should be inversely proportional to the square root of the velocity of the body
• b)
  Force should be inversely proportional to the velocity of the body
• c)
  Force should be directly proportional to the velocity of the body
• d)
  Force should not be varied. It should remain constant with the velocity

 In the given figure, what is the work done by the spring force?

• a)
  
• b)
  
• c)
  
• d)
  

• a)
  1225 W
• b)
  12250 W
• c)
  122.5 W
• d)
  122 W

• a)
  5 J
• b)
  5000 J
• c)
  500 J
• d)
  5 x 10⁵ J

• a)
  momentum
• b)
  kinetic energy
• c)
  both momentum and kinetic energy
• d)
  neither momentum nor kinetic energ

• a)
  moves with the same velocity but in opposite direction
• b)
  move with twice its initial velocity
• c)
  moves with the same velocity in the same direction
• d)
  come to rest.

• a)
  newton meter
• b)
  electron volt
• c)
  joule/meter
• d)
  kilowatt hour

• a)
  Work done in closed path is zero
• b)
  Work done is recoverable
• c)
  Path independent
• d)
  Path dependent

• a)
  The force is always perpendicular to its velocity
• b)
  The force is always perpendicular to its acceleration
• c)
  The object is stationary but the point of application of the force moves on the object.
• d)
  The object moves in such a way that the point of application of the force remains fixed.

• a)
  only when spring is stretched
• b)
  only when spring is compressed
• c)
  when spring is neither stretched nor compressed
• d)
  when spring is compressed or stretched

• a)
  12 m
• b)
  15 m
• c)
  8 m
• d)
  10 m

 A machine, in an amusement park, consists of a cage at the end of one arm, hinged at O. The cage revolves along a vertical circle of radius r (ABCDEFGH) about its hinge O, at constant linear speed

v = . The cage is so attached that the man of weight `w' standing on a weighing machine, inside the cage, is always vertical. Then which of the following is correct
                

• a)
  The reading of his weight on the machine is the same at all positions
• b)
  The weight reading at A is greater than the weight reading at E by 2 w.
• c)
  The weight reading at G = w
• d)
  The ratio of the weight reading at E to that at A=0
• e)
  The ratio of the weight reading at A to that at C=2

Two moving particle P and Q are 10 m apart at a certain instant. The velocity of P is 8m/s making an angle 30° with the line joining P and Q and that of Q is 6m/s making an angle 30° with PQ as shown in the figure. Then angular velocity of P with respect to Q is

                          

• a)
  Zero 
• b)
  0.1 rad/sec
• c)
  0.4 rad/sec
• d)
  0.7 rad sec

• a)
  mgh
• b)
  
• c)
  mv²
• d)
  

• a)
  ectrostatic force
• b)
  Non conservative force
• c)
  conservative force
• d)
  nuclear force

• a)
  increases
• b)
  decreases
• c)
  remains unaltered
• d)
  there is no relationship between force and potential energy

• a)
  2.4  kj
• b)
  5.4 kj
• c)
  5.9 kJ
• d)
  3.8 kJ

• a)
  Viscous force
• b)
  Frictional force
• c)
  Electrostatic force
• d)
  Air-resistance

• a)
  0.25 J
• b)
  12 J
• c)
  8 J
• d)
  1 J

• a)
  kinetic energy is positiv
• b)
  potential energy is positive
• c)
  kinetic energy is negative
• d)
  potential energy is negative

• a)
  100kW
• b)
  100W
• c)
  1kW
• d)
  10kW

• a)
  Infinity
• b)
  Constant
• c)
  Zero
• d)
  sinθ

• a)
  Restoring force of spring
• b)
  Force between two stationary masses
• c)
  Force between two stationary charges
• d)
  Human push or pull

• a)
   KE remains constant
• b)
   Momentum increases
• c)
   KE decreases
• d)
   KE increases

A bomb at rest on a horizontal frictionless surface explodes and breaks into three pieces that fly apart horizontally as shown below. Select all of the following statements that must be true after the bomb has exploded.

1. The total kinetic energy of the bomb fragments is the same as that of the bomb before explosion.
2. The total momentum of the bomb fragments is the same as that of the bomb before explosion.
3. The total momentum of all the bomb fragments together is zero.

• a)
  1,2 and 3
• b)
  1 only
• c)
  3 only
• d)
  2 only

• a)
  
• b)
  
• c)
  
• d)
  

• a)
  product of force and displacement
• b)
  force divided by the displacement
• c)
  definite integral of force over displacement
• d)
  differentiation of force with displacement

• a)
  increases 4 times
• b)
  increases 2 times
• c)
  decreases 4 times
• d)
  decreases 2 times

• a)
  t^3/2
• b)
  t^3/4
• c)
  t^1/4
• d)
  t^1/2

• A:

  2.22 kg

• B:

  2.25 kg

• C:

  2 N/kg

• D:

  1.25 N/kg

The answer is d.

• a)
  5 R
• b)
  4 R
• c)
  2.5 R
• d)
  2 R

• a)
  Kinetic energy
• b)
  Potential energy
• c)
  Linear momentum
• d)
  Velocity