Question

Two ice pucks (one orange and one blue) of equal mass are involved in a perfectly elastic glancing collision as shown in the figures below. The orange puck is initially moving to the right at voi = 4.45 m/s, strikes the initially stationary blue puck, and moves off in a direction that makes an angle of 0 = 35.0° with the horizontal axis while the blue puck makes an angle of o = 55.00 with this axis as in the second figure. Vof Before collision After collision Note that for an elastic collision of two equal masses, the separation angle + 0 = 90.00. Determine the speed of each puck after the collision in meters per second. Vor = Vues m/s m/s

Answer 1

let m is the mass of each puck.

mo = mb = m

Apply conservation of momentum in y-direction

Piy = Pfy

0 = mo*vof*sin(35) - mb*vbf*sin(55)

mo*vof*sin(35) = mb*vbf*sin(55)

vof/vbf = sin(55)/sin(35)

vof = 1.428*vbf

Apply conservation of momentum in x-direction

mo*voi = mo*vof*cos(35) + mb*vbf*cos(55)

voi = vof*cos(35) + vbf*cos(55)

4.45 = 1.428*vbf*cos(35) + vbf*cos(55)

4.45 = vbf*(1.428*cos(35) + cos(55))

==> vbf = 4.45/(1.428*cos(35) + cos(55))

= 2.55 m/s

vof = 1.428*vbf

= 1.428*2.55

= 3.64 m/s

vof = 3.64 m/s <<<<<<-------------Answer
vob = 2.55 m/s <<<<<<-------------Answer