The resultant of the following three couples 20 kg force, 0.5 m arm, $ ve sense 30 kg force, 1 m arm, – ve sense 40 kg force, 0.25 m arm, + ve sense having arm of 0.5 m will be_________________?
(A) 20 kg, – ve sense
(B) 20 kg, + ve sense
(C) 10 kg, + ve sense
(D) 10 kg, – ve sense
(D) 45 kg, + ve sense
The coefficient of friction depends on_________________?
(A) area of contact
(B) shape of surfaces
(C) strength of surfaces
(D) nature of surface
(D) all 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
(D) friction resistance
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
(D) none of the above
Frictional force encountered after commencement of motion is called________________?
(A) post friction
(B) limiting friction
(C) kinematic friction
(D) frictional resistance
(D) dynamic friction
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
(D) none of the above is wrong statement
A particle moves along a straight line such that distance (x) traversed in t seconds is given by x = t2 (t – 4), the acceleration of the particle will be given by the equation_________________?
(A) 3t2-lt
(B) 3t2+2t
(C) 6f-8
(D) 6f-4
(D) 6t2-8t
A projectile is fired at an angle 9 to the vertical. Its horizontal range will be maximum when 9 is_________________?
(A) 0°
(B) 30°
(C) 45°
(D) 60°
(D) 90°
A heavy ladder resting on floor and against a vertical wall may not be in equilibrium, if______________?
(A) the floor is smooth, the wall is rough
(B) the floor is rough, the wall is smooth
(C) the floor and wall both are smooth surfaces
(D) the floor and wall both are rough sur-faces
(D) will be in equilibrium under all condi-tions
Two coplanar couples having equal and op-posite moments_________________?
(A) balance each other
(B) produce a couple and an unbalanced force
(C) are equivalent
(D) produce a moment of couple
(D) can not balance each other