120. Which of the following is the unit of energy
A.Jouls
B.N-m
C.Electron-volt
D.All of the above

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121. A 13 m ladder is placed against a smooth vertical wall with its lower end 5 m from the wall. What should be the coefficient of friction between ladder and floor so that it remains in equilibrium
A.0.1
B.0.15
C.0.2
D.0.21

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122. The tension in the cable supporting a lift is more when the lift is
A.Moving downwards with uniform velocity
B.Moving upwards with uniform velocity
C.Stationary
D.Moving upwards with acceleration

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123. A particle while sliding down a smooth plane of 19.86 √2 m length acquires a velocity of 19.86 m/sec. The inclination of plane is
A.30°
B.45°
C.60°
D.75°

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124. A man wishes to move a block of size 2 m x 2 m, weighing 100 kg. Coefficient of friction between block and floor is 0.3. How he can move it with least effort ?
A.Slide along ground by pushing
B.Tip it over
C.It is not possible to move it
D.Pull it

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125. The product of mass and velocity is known as
A.Work
B.Moment
C.Impulse
D.Momentum

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126. For a machine to be self-locking, its efficiency should be
A.100%
B.Less than 67%
C.Less than 50%
D.More than 50%

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