Question

Two person are raising a load pulling at an angle of each other. If they exert forces of 30N and 60N respectively and their effective pull is at right angle to the direction of the pull of the first person,what is the angle between their pulling force ? What is the effective pull?

Answer 1

Explanation:

Here A= 30N , B=60N , C=90^°

Let D be the angle between 2 forces. Then tan C =BsinD/A+B cosD

or tan 90^°=60sinD/30+60cosD  

or 30+60cosD =0

or cosD=-30/60 =-1/2 =cos120^°

or D=120^°

Effective pulling force is  

R= root A^2+B^2+2ABcosD

=root 900+3600+2×30×60 (-1/2)

=30root3N