The collar has a mass of 2 kg and is attached to the light spring, which has a stiffness of 30 N∕m and an un- stretched length of 1.5 m. The collar is released from rest at A and slides up the smooth rod under the action of the con- stant 50-N force. Calculate the velocity v of the collar as it passes position B. Use point A as datum.

The spring has a stiffness k = 50 lb/ft and an unstretched length of 2 ft. As shown, it is confined by the plate and wall using cables so that its length is 1.5 ft. A 5-lb block is given a speed A when it is at A, and it slides down the incline having a coefficient of kinetic friction µ = 0.2. It strikes the plate and pushes it forward 0.25 ft before stopping. Neglect the mass of the plate and spring. (Figure 1), Figure k = 50 lb/ft 1.5 ft 3 ft

3/156 The two 1.5-kg spheres are released from rest and gently nudged outward from the position = 0 and then rotate in a vertical plane about the fixed centers of their attached gears, thus maintaining the same angle for both rods. Determine the ve- locity v of each sphere as the rods pass the position 0 = 30°. The spring is unstretched when 0 = 0, and the masses of the two identical rods and the two gear wheels may be neglected. 1.5 kg 240 mm 240 mm k = 60 N/m 80 mm Problem 3/156 1.5 kg

The simple pendulum A of mass ma = 3.9 kg and length I = 1.51 m is suspended from the trolley B of mass me = 7.9 kg. If the system isreleased from rest at 0 = 0, determine the velocity g (positive if to the right, negative if to the left) of the trolley when 0 = 90° Friction is negligible.