An 80pound weight is lying on a situp bench at the gym If th

An 8.0-pound weight is lying on a sit-up bench at the gym. If the bench is inclined at an angle of 5°, there are three forces acting on the weight, as shown in the figure. N is called the normal force and it acts in the direction perpendicular to the bench. F is the force due to friction that holds the weight on the bench. If the weight does not move, then the sum of these three forces is 0. Find the magnitude of N and the magnitude of F. (Round each answer to one decimal place.)

Solution

magnitude of F= 8*sin5° =8* 0.0871 = 0.6972lb =0.69lb~0.7lb

magnitude of N = 8*cos5° = 8*0.996 = 7.9 68lb =7.9lb