3/199 The hydraulic braking system for the truck and trailer is set to produce equal braking forces for the two units. If the brakes are applied uniformly for 5 seconds to bring the rig to a stop from a speed of 20 mi/hr down the 10-percent grade, determine the force P in the coupling between the trailer and the truck. The truck weighs 20,000 lb and the trailer weighs 15,000 lb. 20 mi/hr 10 3/200 Problem 3/199