Question

Two shuffleboard disks of equal mass, one orange and the other yellow, are involved in a perfectly elastic, glancing collision. The yellow disk is initially at rest and is struck by the orange disk moving with a speed of 3.64 m/s. After the collision, the orange disk moves along a direction that makes an angle of 51.2 degreeswith its initial direction of motion and the velocity of the yellow disk is perpendicular to that of the orange disk (after the collision). Determine the final speed of the orange disk.

Answer 1

90 -51.2 = 38.8
initial momentum in x direction
m * 3.64
in y direction zero
final orange momentum
x direction = m U cos 51.2
y direction = m U sin 51.2
final yellow momentum
x direction = m V cos 38.8
y direction = -m V sin 38.8
Final momentum vector = initial = m * 3.64 in x and 0 in y
so
equation 1 ----- > 3.64 m = m U cos 51.2 + m V cos 38.8
and
equation 2 ---- > 0 = m U sin 51.2 - m V cos 38.8
m cancels obviously. Solve the two equations for U