14-89. The 10-kg block A is released from rest and slides down the smooth plane. Determine the compression x of the spring when the block momentarily stops. k = 5 kN/m 30° 10 m

*13-100. For a short time, the 250-kg roller-coaster car with passengers is traveling along the spiral track at a constant speed of v= 8 m/s. If the track descends d = 12 m for every full revolution, 0 = 27 rad, determine the magnitudes of the components of force which the track exerts on the car in the r.0, and z directions. Neglect the size of the car. 13-101. For a short time, the 250-kg roller-coaster car with passengers is traveling along the spiral track at a constant speed such that its position measured from the top of the track has components r=10m, 0=(0.2t) rad, and z=(-0.3t) m, where t is in seconds. Determine the magnitudes of the components of force which the track exerts on the car in the r, 0, and z directions at the instant t = 2 s. Neglect the size of the car. r = 10 m on Why d

(25 pts) The 50-lb block rests on the smooth surface. A force F = (40+s²) lb, which s is in ft, acts on the block in the direction shown. If the spring is originally unstretched (s = 0) and the block is at rest, determine the power developed by the force the instant the block has moved s = 1.5 ft. F. 30° k = 20 lb/ft wwwwww

4 m M = (30t²) N•m F = 15t N. If the rod of negligible mass is subjected to a couple moment of M=29t2 N;M where t is the time in seconds, and the engine of the car supplies a braking force F= 15t N to the wheels, determine the speed of the car at t= 8s. The car at t=0s a a speed of 7 m/s. The total mass of the car and the driver is 158 kg. Neglect the size of the car.