# Resultant Force

• Apr 25th 2009, 03:34 PM
Tek
Resultant Force
Forces with magnitudes of 85 pounds and 50 pounds act on a single point. The angle between the forces is 15 degrees. Describe the resultant force.

The answer in the book is: "The resultant force is 113.92 pounds and 5.6 degrees from the 85-pound force."

For the life of me I cannot understand how to obtain this answer though...
• Apr 25th 2009, 04:30 PM
galactus
Is there a diagram to go along with the problem?. That may help.

Try the law of cosines.

$75+\sqrt{85^{2}+50^{2}-2\cdot 85\cdot 50\cdot cos(15)}\approx 113.92$
• Apr 25th 2009, 04:33 PM
VonNemo19
Now go solve this thing!
Hey Tek, A parrallelogram is formed from the two added force vectors. The law of cosines is all you need to solve this problem.