Question

Two gliders on an air track collide in a perfectly elastic collision. Glider A has a mass of 1.1 kg and is initially travelling at a velocity of 2.7 m/s [E]. It collides head-on with glider B with a mass of 2.4 kg, travelling at a velocity of 1.9 m/s [W]. Determine the final velocity of glider A.

Answer 1

m1= mass 1 = 1.1 kg

Vi1 = initial velocity 1 = 2.7 m/s

m2= 2.4 kg

V2i = -1.9 m/s

We assume east as positive and west as negative.

Apply the formulas:

Vf1 = ?

$vf1=(\frac{m1-m2}{m1+m2})Vi1+(\frac{2m2}{m1+m2})Vi2$

Replacing:

$Vf1=\frac{(1.1-2.4)}{(1.1+2.4)}2.7+\frac{(2\times2.4)}{(1.1+2.4)}-1.9$$Vf1=(\frac{-1.3}{3.5})2.7+(\frac{4.8}{3.5})-1.9$$Vf1=-1-2.6=-3.6\text{ m/s}$

Answer: 3.6 m/s west