Question

Forces of 10.4 N north, 19.7 N east, and 15.3 N south are simultaneously applied to a 3.73 kg mass as it rests on an air table.

a)What is the magnitude of its acceleration?

b)What is the direction of the acceleration in degrees? (Take east to be 0 degrees and counterclockwise to be positive.)

I got a), but for b) I got 346 degrees and it was wrong

i didn't use the mass for any thing...was i supposed to?

Answer 1

Y force (North) = 10.4 - 15.3 = -4.9
X force (East) = 19.7
Net force in quadrant 4

magnitude = sqrt(19.7^2+ (-4.9)^2 )
= 412 N

angle below x axis = tan^-1 (4.9/19.7)
angle = 14 degrees or 360 - 14 = 346 counterclockwise from x axis
346 is right, so is -14