Wright State University
Department of Mechanical and Materials Engineering
Fall 2013
ME 2210 DYNAMICS: QUIZ 4
Open Book, Closed Notes, DO NOT Write on this Sheet
Show All Work for Partial Credit
Problem 1 (20 points): Two small spheres A and B, weighing WA = 5 lb and WB = 2 lb, respectively, are
connected by a rigid rod of negligible weight. The two spheres are resting on a horizontal, frictionless surface
when B is suddenly given the velocity ⃗⃗⃗⃗⃗⃗ = (10.5) ̂ ft/s. Using the principle of conservation of linear
momentum of the system, and the principle of conservation of angular momentum of the system about its mass
center G, and the principle of conservation of energy, determine the magnitudes and directions of the velocities
of spheres A and B after the rod AB has rotated through 90º. At the initial position, the following quantities are
provided:
⃗⃗⃗⃗
) ̂ lb-s, ⃗⃗⃗⃗⃗⃗⃗
(
) ̂ ft-lb-s,
(
ft-lb
A
G
7 inches
A
B
5 inches
B
Position 1
y
x
⃗⃗⃗⃗⃗⃗
𝑣𝐵
Position 2