Question

A block weighing 200 N is just moved on a rough horizontal plane by a pull of

90 Newton acting at an angle of 30 degree with the horizontal. Determine:

(i) the coefficient of friction .

(ii) Push that should be applied to the block at the same angle to

attain the condition of limiting equilibrium.​

Answer 1

According to question,

So,The force on the block long the horizontal is  

F  

x

​

=100cos30−f⋯(i)

f=μ×N⋯(ii)

and also,

200=N+100sin30

N=150N

Now,

substituting the above value  in (ii)

f=150×μ

substituting the value  of  

′

f  

′

  in (i)

F  

x

​

=100cos30−150×μ

Hence, the block moves with the constant velocity it means that there is no net force acting on it is horizontal direction,

F  

x

​

=0

100cos30−150×μ=0

86.6025=150×μ

μ=0.57735