question_answer

A body of weight 50 N placed on a horizontal surface is just moved by a force of\[28.2\text{ }N\]. The frictional force and the normal reaction are

A) \[10\,N,15\,N\]    

B)        \[20\,N,30\,N\]

C) \[2\,N,3\,N\]             

D)        \[5\,N,6\,N\]

Correct Answer: B

Solution :

[b] Friction force \[=f=28.2\cos 45{}^\circ =28.2\times \frac{1}{\sqrt{2}}=20N\] Normal reaction \[R=50-28.2\sin 45{}^\circ =30N\]