Past Year Questions: Friction - Mechanical Engineering MCQ

The figure shows a pair of pin-jointed grippertongs holding an object weighing 2000 N. The coefficient of friction (μ) at the gripping surface is 0.1. XX is the line of action of the input force and YY is the line of application of gripping force. If the pin- joint is assumed to be frictionless, the magnitude of force F required to hold the weight is

[2004]

Two books of mass 1 kg each are kept on a table, one over the other. The coefficient of friction on every pair of contacting surfaces is 0.3. The lower book is pulled with a horizontal force F. The minimum value of F for which slip occurs between the two books is

[2005]

A block of mass M is released from point P on a rough inclined plane with inclination angle θ, shown in the figure below. The coefficient of friction is μ. If μ < tan θ, then the time taken by the block to reach another point Q on the inclined plane, where PQ = s, is

[2007]

​A block weighing 981 N is resting on a horizontal surface. The coefficient of friction between the block and the horizontal surface is m = 0.2. A vertical cable attached to the block provides partial support as shown. A man can pull horizontally with a force of 100 N. What will be the tension, T (in N) in the cable if the man is just able to move the block to the right?

[2009]

​A 1 kg block is resting on a surface with coefficient of friction m = 0.1. A force of 0.8 N is applied to the block as shown in the figure. The friction force is

[2011]

A block R of mass 100 kg is placed on a block S of mass 150 kg as shown in the figure. Block R is tied to the wall by a massless and inextensible string PQ. If the coefficient of static friction for all surfaces is 0.4, the minimum force F(in kN) needed to move the block S is

[2014, Set-1]

A wardrobe(mass 100 kg, height4m, width 2 m, depth 1 m), symmetric about the Y-Y axis, stands on a rough level floor as shown in the figure. A force P is applied at mid-height on the wardrobe so as to tip it about point Q without slipping. What are the minimum values of the force (in newton) and the static coefficient of friction μ between the floor and the wardrobe, respectively?

[2014, Set-4]