Here's the problem. Five children are pushing on a snowball, each pushing with a force of 10 N. Each is pushing at an angle of 45 relative to his neighbor. What is the net push on the ball? Ok my prof went over this problem in class but moved through it so fast that I didn't understand what he did. Here's what I have. I draw a ball (the snowball) with 5 vectors at 45 degree angles to each other. This leads to the two vectors at opposite ends cancelling each other out, so I'm left with 3 vectors all 45 degrees to each other. Ok I know the left most vector and the right most vector are putting resistance on each other... but I'm not sure how he went about this, He did 10 Sin 45 for the first vector, + 10 N, and then 10 sin 45 for the 3rd vector all summed up = 24.1 N. but how do you know to do 10 sin 45?