A. bodies having relative motion
B. two dry surfaces
C. two lubricated surfaces
D. solids and liquids
E. electrically charged particles
Related Mcqs:
- Dynamic friction as compared to static friction is________________?
A. same
B. more
C. less
D. may be less of more depending on nature of surfaces and velocity
E. has no correlation - Pick up wrong statement about friction force for dry surfaces. Friction force is________________?
A. proportional to normal load between the surfaces
B. dependent on the materials of contact surface
C. proportional to velocity of sliding
D. independent of the area of contact surfaces
E. none of the above is wrong statement - On the ladder resting on the ground and leaning against a smooth vertical wall, the force of friction will be__________________?
A. downwards at its upper end
B. upwards at its upper end
C. perpendicular to the wall at its upper end
D. zero at its upper end
E. none of the above - Kinetic friction is the________________?
A. tangent of angle between normal reac-tion and the resultant of normal reac-tion and the limiting friction
B. ratio of limiting friction and normal reaction
C. the friction force acting when the body is just about to move
D. the friction force acting when the body is in motion
E. dynamic friction - A semi-circular disc rests on a horizontal surface with its top flat surface horizontal and circular portion touching down. The coefficient of friction between semi-cricular disc and horizontal surface is i. This disc is to be pulled by a horizontal force applied at one edge and it always remains horizontal. When the disc is about to start moving, its top horizontal force will____________________?
A. remain horizontal
B. slant up towards direction of pull
C. slant down towards direction of pull
D. unpredictable
E. none of the above - The effort required to lift a load W on a screw jack with helix angle a and angle of friction <j) is equal to_________________?
A. Wtan(a + )
B. Wtan(a-)
C. Wcos(a + )
D. Wsin(a + )
E. W (sin a + cos ) - Tangent of angle of friction is equal to_________________?
A. kinetic friction
B. limiting friction
C. angle of repose
D. coefficient of friction
E. friction force - On a ladder resting on smooth ground and leaning against vertical wall, the force of friction will be__________________?
A. towards the wall at its upper end
B. away from the wall at its upper end
C. upwards at its upper end
D. downwards at its upper end
E. none of the above - The ratio of limiting friction and normal reaction is known as_______________?
A. coefficient of friction
B. angle of friction
C. angle of repose
D. sliding friction
E. friction resistance - The coefficient of friction depends on_________________?
A. area of contact
B. shape of surfaces
C. strength of surfaces
D. nature of surface
E. all of the above
