Question

2 forces of 5 N and 7 N act on a particle with an angle of 60° between them. Find the resultant force.

Answer 1

f1 = 5N
f2 = 7N

theta = 60°

$fnet = f1 {}^{2} + f2 {}^{2} + 2f1f2cos \: theta$

$= 5 {}^{2} + 7 {}^{2} + 2 \times 5 \times 7 \times cos60$

$= 25 + 49 + 70 \times (\sqrt{3} \div 2 )$

$= 74 + 35 \sqrt{3}$


Thanks