## Fundamentals of Physics Extended (10th Edition)

The first thing we do for problems with a ramp is to set our coordinate axes so that the x axis is parallel to the plane and the y axis is perpendicular to it. We then need to resolve Fg (Force of the weight of the block) into its x and y components in the new coordinate system. Using the angle given and similar triangles, we find that Fg,x = Fgsin($\theta$) and that Fg,y = Fgcos($\theta$). To find the Normal Force, we need to find all the forces acting on the block in the y direction. These are the Normal Force acting upwards and Fg,y acting downwards. Since the block is not moving, the net Force must be 0 meaning that N - Fg,y= 0. Therefore, N = Fg,y = (8.5kg)(9.8\$m/s^2)cos(30) = 72N