Question

A block rests on a rough inclined plane making an angle of 30∘with the horizontal. the coefficient of static friction between block and the plane is 0.8. if the frictional force on the block is 10 n, the mass of block is

Answer 1

friction force = coefficient of friction × mgcos30°

Answer 2

From figure , it is clear that the block of mass m , rests on inclined plane due to frictional force .

Hence ,

mgsinθ=f

s

.............eq1

given θ=30

o

,f

s

=10N,g=10m/s

2

Therefore , by eq1

m×10×sin30=10

or m×1/2=1

or m=2kg