im studying for a test, unfortunately i seem to be having difficulty with the simple problems, so i decided to try some practice problems: 1. two forces, each of 100N, act on an object having a mass of 40 kg. What is the magnitude of the net acceleration of the object if one of the forces is directed upward and the other is to the left? the answer it says is 3.5 m/s^2. i know net external force=mass x acceleration, so i tried figuring out the net external force and I think that's where I get confused. because force is mass times acceleration? ug i dont know. can someone help please? ******* oh thank you so much!! i got it now, square root of (100^2 + 100^2) then divide by 40. may i ask another one? a 250-N weight is suspended in equilibrium by two cables. one cable applies a horizontal force to the right. the other cable applies a force upward to the left at an angle of 45 deg. to the negative x-axis. what is the tension in the second cable? answer: 350 N -how do you incorporate the first cable into figuring out for the second? i've tried solving this a couple of days ago, and still can't. any type of hint would be helpful!