Explanation:
Let's solve the problem by using conservation of momentum:
m1 u1 + m2 u2 = m1 v1 + m2 v2
where:
m1 = 3.5 g is the mass of the blue marble
m2= 1.2 g is the mass of the red marble
u1 = 15 cm/s is the initial velocity of the blue marble
u2 = 3.5 cm/s is the initial velocity of the red marble
v1 = 5.5 cm/s is the final velocity of the blue marble
We can find the final velocity of the red marble by re-arranging the equation and solving for v2 :
v2 = 1/m²(m1 u1 + m2 u2 - m1 v1)=
=1/1.2(3.5×15+1.2×3.5−3.5×5.5 )=31cm/s
