Engineering Mechanics - KOP: Force and Acceleration - Discussion

A truck T has a weight of 8,000 lb and is traveling along a portion of a road defined by the lemniscate r² = 0.2(106) cos 2 , where r is measured in feet and is in radians. If the truck maintains a constant speed of vr = 4 ft/s, determine the magnitude of the resultant frictional force which must be exerted by all the wheels to maintain the motion when = 0.