Chapter 15, Problem 57P

1. A 20-lb collar slides without frictions along a vertical rod as shown. The elastic rope attached to the collar has an undeformed length of 4 inches and spring constant of 3 lb/in. If the collar is released from rest in position A, determine its velocity at position B. Apply conservation of energy. 8 in 6 in B 2. The 200 gram toy car will be compressed against the spring and released to send it around the loop which has diameter of 60 cm. Determine minimum reauired spring compression to maintain contact with the tack for the entire

A constant force of ''F'' acts on a mass as shown. The mass starts its motion from rest at position 1, the unstretched length of the spring is 250 mm, and the spring modulus is k=1,5 k?/m. Neglecting the friction, determine the required force ''F'' to cause the 2−kg mass to have a speed of v2=1,5 m/s at position 2.

2. Crates A and B weigh 100 lb and 50 lb, respectively. If they start from rest, determine their speed when t = 5 s. Also, find the force exerted by crate A on crate B during the motion. The coefficient of kinetic friction between the crates and the ground is = 0.25. A P = 50 lb B