Work and Energy


A ball balanced on a vertical rod is an example of

  1. stable equilibrium
  2. unstable equilibrium
  3. neutral equilibrium
  4. perfect equilibrium
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Which one of the following is the value of 1 kWh of energy converted into joules?

  1. 1.8 × 106 J
  2. 3.6 × 106 J
  3. 6.0 × 106 J
  4. 7.2 × 106 J
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Two bodies A and B having masses m and 4m respectively are moving with equal linear momentum. The ratio of kinetic energies between A and B is

  1. 1 : 2
  2. 1 : 1
  3. 4 : 1
  4. 1 : 4
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Two cars A and B have masses mA and mB respectively, with mA > mB. Both the cars are moving in the same direction with equal kinetic energy. If equal braking force is applied on both, then before coming to rest

  1. A will cover a greater distance
  2. B will cover greater distance
  3. both will cover the same distance
  4. distance covered by them will depend on their respective velocities
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The force acting on a particle of mass m moving along the x-axis is given by F(x) = Ax2 - Bx. Which one of the following is the potential energy of the particle?

  1. 2Ax - B
  2. -x2/6 (2Ax - 3B)
  3. Ax3 - Bx2
  4. Zero
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A body is falling from a height h. After it has fallen a height h/2, it will possess

  1. only potential energy
  2. only kinetic energy
  3. half potential and half kinetic energy
  4. more kinetic and less potential energy
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The work done on an object does not depend upon the

  1. displacement
  2. force applied
  3. angle between force and displacement
  4. initial velocity of the object
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An iron sphere of mass 10 kg has the same diameter as an aluminium sphere of mass is 3.5 kg. Both spheres are dropped simultaneously from a tower. When they are 10 m above the ground, they have the same

  1. acceleration
  2. momenta
  3. potential energy
  4. kinetic energy
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In case of negative work the angle between the force and displacement is

  1. 45°
  2. 90°
  3. 180°
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A car is accelerated on a levelled road and attains a velocity 4 times of its initial velocity. In this process the potential energy of the car

  1. does not change
  2. becomes twice to that of initial
  3. becomes 4 times that of initial
  4. becomes 16 times that of initial
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When a body falls freely towards the earth, then its total energy

  1. increases
  2. decreases
  3. remains constant
  4. first increases and then decreases
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