- #1

Turquoise

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## Homework Statement

Two forces are acting on a mass. One of the forces is a 40.0 N force and the other force is 30.0 N at the angles shown below:

The magnitude of the force is:

a) 15.3 N

**b) 15.6 N**<-- correct answer

c) 46.6 N

d) 69.0 N

## Homework Equations

Pythagorean Therom

Cosine, Sine

## The Attempt at a Solution

Vector

X component

A ax = (30.0N) Cos 20.0 = 28.2 N

B bx = (40.0 N)Cos 40.0 N = 30.6 N

Y component

ay = (30.0N)Sin 20.0 = 10.3 N

by = (40.0 N) Sin 40.0N = 25.7 N

C = ax+bx = 58.8 N Cy = 36 N

C = cx^2 + cy^2

C = 58.8N^2 + 36 N^2

C = 69 N

I keep getting 69 N and its not the correct answer. The correct answer is 15.6. I'm following the directions from my notes, but it gives me 69 every time. Help! What am I doing wrong?