Question

Figure shows a force $F=\hat{i}+4\hat{j}$ acts on a $1kg$ block . What is the force of friction acting on the block ?

• A. $-\hat{i}$
• B. $-1.8\hat{i}$
• C. $-2.4\hat{i}$
• D. $-3\hat{i}$

Answer 1

Answer: (A)

$f=\hat{i}+4\hat{j}m=1kg$
$mg=10$
$N+4=mg$
$N+4=10$
$N=6$
$F_{m a x}=\mu N$
$=0.3\times 6=1.8N$

Force in horizontal direction is 1N which is less than 1.8N then force of frictions is $-\hat{i}$