Question: The effort required to lift a load W on a screw jack with helix angle a and angle of friction

• 1. Wtan(a + )
• 2. Wtan(a-)
• 3. Wcos(a + )
• 4. Wsin(a + )

Question: Tangent of angle of friction is equal to_________________?

• 1. kinetic friction
• 2. limiting friction
• 3. angle of repose
• 4. coefficient of friction

Question: Coulomb friction is the friction between_________________?

• 1. bodies having relative motion
• 2. two dry surfaces
• 3. two lubricated surfaces
• 4. solids and liquids

Question: A projectile is fired at an angle 9 to the vertical. Its horizontal range will be maximum when 9 is_________________?

• 1. 0°
• 2. 30°
• 3. 45°
• 4. 60°

Question: 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_________________?

• 1. 3t2-lt
• 2. 3t2+2t
• 3. 6f-8
• 4. 6f-4

Question: Pick up wrong statement about friction force for dry surfaces. Friction force is________________?

• 1. proportional to normal load between the surfaces
• 2. dependent on the materials of contact surface
• 3. proportional to velocity of sliding
• 4. independent of the area of contact surfaces

Question: Frictional force encountered after commencement of motion is called________________?

• 1. post friction
• 2. limiting friction
• 3. kinematic friction
• 4. dynamic friction

Question: On a ladder resting on smooth ground and leaning against vertical wall, the force of friction will be__________________?

• 1. towards the wall at its upper end
• 2. away from the wall at its upper end
• 3. upwards at its upper end
• 4. downwards at its upper end

Question: The ratio of limiting friction and normal reaction is known as_______________?

• 1. coefficient of friction
• 2. angle of friction
• 3. angle of repose
• 4. sliding friction

Question: The coefficient of friction depends on_________________?

• 1. area of contact
• 2. shape of surfaces
• 3. strength of surfaces
• 4. nature of surface