Physics
posted by Rams .
1.Three forces in the xy plane act on a 2.9 kg mass: 11.1 N directed at 20, 14.2 N directed at 131 , and 12.2 N directed at 201 . All angles are measured from the positive xaxis, with positive angles in the CounterClockwise direction. Calculate the magnitude of the acceleration.
Calculate the direction of the resultant force using the same sign convention as above in degrees
2.A person walks on level ground 0.7 km east, then 300 meters south, and then climbs to the top of the Washington Monument (height 180 meters). What is the net displacement of the person?
3.Calculate the normal force exerted on a 2.81 kg book resting on a surface inclined at 32.2 above the horizontal

The distance between intital and final locations is the square root of the sum of the squares of the three movements, since they are are perpendicalar to one another.
In meters, that would be
sqrt[(700)^2 + (300)^2 + (180)^2] = ?
Please show your work and avoid multiple posts. 
procedure of inverse square fpr ligth