Q. A cylinder of radius 250 mm and weight, W = 10 kN is rolled up an obstacle of height 50 mm by applying a horizontal force P at its centre as shown in the figure.
All interfaces are assumed frictionless. The minimum value of P is
(A) 4.5 kN (B) 5.0 kN (C) 6.0 kN (D) 7.5 kN
Ans: 7.5 kN
Sol:
When the roller will just start to roll up, then it will loose its contact at point X. only contact will be at point B.
