Two friends, al and jo, have a combined mass of 137 kg. at an ice skating rink they stand close together on skates, at rest and facing each other, with a compressed spring between them. the spring is kept from pushing them apart, because they are holding each other. when they release their arms, al moves off in one direction at a speed of 1.18 m/s, while jo moves off in the opposite direction at a speed of 1.37 m/s. assuming that friction is negligible, find al's mass.

63.4 kg

Explanation:

This is a shock problem that must be solved with the conservation of the moment, for this we create a system formed by the two friends (Al and Jo) and the spring, so the forces that act are internal and the moment is conserved

Initial         p₀ = 0

Final       = m₁ v₁ + m₂ v₂

Assign Al letter 1 and Jo letter 2

                p₀ =  

                0 = m₁ v₁ + m₂ v₂

                m₁ / m₂ = - v₂ / v₁

                m₁ / m₂ = - 1.37 / -1.18

                m₁ / m₂ = 1,161

                m₁ = 1,161 m₂

In addition, we combined mass

               m₁ + m₂ = 137 Kg

               (1,161 m₂) + m₂ = 137

               2,161 m₂ = 137

               m₂ = 63.4 kg

0.19 m/s and 0.45 m/s