UPSEE Solved Model Paper 2

Weight of mass m2 = 6 × 10 = 60 N. The weight of m2 provides the tension. Thus
T = 60 N
Opposing this force along the plane is the component F1 = m1g sin θ of the force m1g. Now F1 = m1gsinθ = 5×10×sin30° = 25 N.
Since F1 is less than T and is, therefore, insufficient to balance T (see Fig.), the force of friction (f) down the plane is necessary to keep block m1 at rest. Thus, f must act down the plane. Since mass m1 is at rest, the net force on m1 along the plane must be zero. Thus

T - m1gsin30°−f = 0
or f = T−m1g si 30°
= 60 - 5 × 10 × sin 30°
= 60 - 25 = 35 N
Hence, the correct choice is (2).