A couple of stones pushing against the base of a builder are preventing it from sliding down the mountain. The force of one stone acting on the boulder with respect to a certain axis is 85.6 N at an angle of 53 degrees and the other is 95.8 N at an angle of -60 degrees. What is the magnitude and direction of the force attempting to push the boulder down the mountain, balancing the other two?

a) b) Draw a qualitative picture of this situation. Choose an xaxis. Sketch in the two known forces. (It is not necessary to make an accurate diagram using a protractor and ruler.) Based on what you have drawn, predict the magnitude and direction of the third vector. (It does not have to match the nal solution exactly: this is just a sketch.) I In a few sentences, describe your problemsolving strategy. What are you going to do, and in what order, to nd a solution to this word problem? Solve to nd the magnitude and direction of the third force. For each step, begin by writing down either one of the equations we have given you in the header or one that is a result of the problem set-up (if you can identify it). Next, replace variables in the equation with numbers from the problem. After one or more algebraic steps, record your answer to that step, including a unit on the value and a reasonable number of signicant digits (not the full calculator display!)