Question

A block is pulled by a force of $20N$ at an angle of 30 degrees from the horizontal. Identify which of the following statement best describes the force between the block and the surface?

• A. The normal force is less than $50N$
• B. The normal force is greater than $50N$
• C. The normal force is equal to $50N$
• D. The coefficient of friction increases as the angle increases
• E. The coefficient of friction decreases as the angle increases

Answer 1

The correct option is A The normal force is less than $50N$

Given : $F=20$ N $W=50$ N

Thus vertical component of the force $F_v=F$ $sin{30}^o=20\times 0.5=10$ N

Let the normal force exerted on the block by the surface be $N$.

$\therefore$ $F_v+N=W$

OR $10+N=50$ $⟹N=40$ N

Hence option A is correct.