-1.5 m 3 m/s k= 100 N/m B Prob. 14-76

15-33. The log has a mass of 500 kg and rests on the ground for which the coefficients of static and kinetic friction are H, = 0.5 and µe = 0.4, respectively. The winch delivers a horizontal towing force T to its cable at A which varies as shown in the graph. Determine the speed of the log when t = 5 s. Originally the tension in the cable is zero. Hint: First determine the force needed to begin moving the log. T (N) 1800 T = 200 t (s) 3 AT

2. The 10-Ib block has a speed of 4 ft's when the force of F= (8t?) Ib is applied. Determine the velocity of the block when t= 2 s. The coefficient of kinetic friction at the surface is = 0.2. v = 4 ft/s F= (8°) lb

-y = 45 - hft k lblft www Ift The 5-lb collar has a speed of 3 ft.s1 at A. The attached spring has an unstretched length of 2- ft and a stiffness of k=17lb.ft1. If the collar moves over the smooth rod, determine its speed when it reaches point B. The height of A is h=9-ft and B is at l=4-ft from the vertical of A

13-27. The conveyor belt is moving downward at 4 m/s. If the coefficient of static friction between the conveyor and the 15-kg package B is µ, = 0.8, determine the shortest time the belt can stop so that the package does not slide on the belt. 4 m/s 30°

5. The 8-kg smooth collar has a speed of 5 m/s when it is at s = 0. Determine the maximum distance s it travels before it stops momentarily. The spring has an unstretched length of 2 m. -1.5 m- -3 m/s k = 100 N/m

13-17. Determine the acceleration of the blocks when the system is released. The coefficient of kinetic friction is µr. and the mass of each block is m. Neglect the mass of the pulleys and cord. B A.

When 0=60°, the boy's center of mass G has a speed of 10 ft/s as he swings to the right. Determine the rate of increase in his speed and the tension in each of the two supporting cords of the swing at that instant. The boy has a weight of 60 lb. 10 í

*14-24. At a given instant the 10-lb block A is moving downward with a speed of 6 ft/s. Determine its speed 2 s later. Block B has a weight of 4 lb, and the coefficient of kinetic friction between it and the horizontal plane is Hi = 0.2. Neglect the mass of the cord and pulleys. в