Chapter 8, Problem 39P

The crane truck has a weight of 10750 lb and a center of gravity at point . The parking brake only locks the rear wheels of the truck, so the front wheels are free to rotate. Determine the maximum force F applied at the angle 0 = 36° that can be exerted on the crane without it slipping or tipping for each of the following cases: Case 1: The static friction coefficient between the rear tires and the ground is μ = 0.060. Case 2: The static friction coefficient between the rear tires and the ground is μ. = 0.35. h CGD . п d k a жь D с LL BY NC SA 2013 Michael Swanbom ၅၁ Values for dimensions on the figure are given in the following table. Note the figure may not be to scale. Variable Value a 5 ft b 9 ft с 5.5 ft d 3.5 ft h 11 ft For Case 1, the constraint is Select an answer Fmax lbs. For Case 2, the constraint is Select an answer F max lbs. and and

Q1: The tractor has a weight of 4500 lb with center of gravity at G. The driving traction is developed at the rear wheels B, while the front wheels at A are free to roll. If the Q2: The mine car and its contents have a total mass of 9 Mg and a center of gravity at G. If the coefficient of static friction between the wheels and the tracks is u, = 0.4 when the wheels are locked, find the normal force acting on the coefficient of static friction between the wheels at B and the ground is u, = 0.5, determine if it is possible to pull at P = 1350 lb without causing the wheels at B to slip or the front wheels at A to lift off the ground. front wheels at B and the rear wheels at A when the brakes at both A and B are locked. Does the car move? 10 kN 0.9 m G 0.15 m 3.5 ft 1.25 ft 0.6 m- 4 ft -1.5 m- 2.5 ft

The pickup truck pulls the wooden crate, as shown in Figure 2. The truck has a mass of 1.25 Mg and a center of mass at G. The coefficient of static friction between the truck's wheel and the ground is µ = 0.5, and between the wooden crate and the ground is µs' = 0.4. Determine the greatest weight of the wooden crate the pickup truck can pull if:   a) the truck has rear-wheel drive while the front wheels are free to roll, and   b) the truck has four-wheel drive.