Question

Masses M₁, M₂ and M₃ are connected by strings of negligible mass which pass over massless and frictionless pulleys P₁ and P₂ as shown in the Figure. The masses move such that the portion of the string between P₁ and P₂ is parallel to the incline and the portion of the string between P₂ and M₃ is horizontal. The masses M₂ and M₃ are 0.4 kg each and the coefficient of kinetic friction between masses and surfaces is 0.25. The inclined plane makes an angle of 37° with the horizontal, however, the mass M₁ moves with uniform velocity downwards. Now, find 

(a) The tension in the horizontal portion of the string

(b) The mass M₁(g = 9.28 ms^-2, sin37° = 3/5)

Answer 1

Apply Newton’s first law for each of the blocks as the velocity of each block is constant.

Let T₁ be the tension between M₁ and M₂ and T₂ be the tension between M₂ and M₃.

Let µ be the coefficient of kinetic friction. Then