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).