Work done by the force of friction is:
A. always positive
B. always negative
C. positive only for small frictional force
D. positive only for large frictional force
The source of geothermal energy is:
A. decay of radioactive element in the earth
B. compression of material in the earth
C. residual lost of the earth
D. all as said in A – B and C
The escape velocity of a body in gravitational field of earth is independent of:
A. its mass
B. the angle at which it is thrown
C. both its mass and the angle at which it is thrown
D. gravitational field of earth
The source of tidal energy is:
A. sun
B. earth
C. both A and B
D. moon
The dot product of force and velocity is:
A. power
B. work
C. impulse
D. torque
The dimension of power is:
A. [ML2T-3]
B. [ML2T-2]
C. [ML2T3]
D. none of these
The work done by friction is:
A. positive
B. negative
C. zero
D. none of these
The escape velocity form the earth surface in km S-1 is:
A. 4.2 km S-1
B. 7.5 km S-1
C. 9.5 km S-1
D. 1.1 km S-1
The consumption of energy by a 60 watt bulb in 2 sec is:
A. 120 J
B. 60 J
C. 30 J
D. 0.02 J
Which of the following is not conservative force:
A. friction
B. electric
C. gravitational
D. magnetic
