Question

A 2-kg ball moving eastward at 3 m/s suddenly collides with and sticks to a 4-kg ball moving northward at 2 m/s. What is the magnitude of the momentum of this system just after the collision

Answer 1

Answer:

p = 10 kg-m/s

Explanation:

Given that,

Mass of ball 1, m₁ = 2 kg

Speed of ball 1, u₁ = 3i m/s (due East)

Mass of ball 2, m₂ = 4 kg

Speed of ball 2, u₂ = 2j m/s (due North)

We need to find the magnitude of the momentum of this system just after the collision. As we have seen that two balls are moving perpendicular to each other.

Momentum of ball 1, p₁ = m₁u₁

p₁ = 2× 3 = 6 kg-m/s (due east)

Momentum of ball 2, p₂ = m₂u₂

p₂ = 4× 2 = 8 kg-m/s (due north)

Net momentum is given by :

$p=\sqrt{p_1^2+p_2^2} \\\\p=\sqrt{6^2+8^2} \\\\p=\sqrt{36+64} \\\\p=10\ kg-m/s$

So, the magnitude of the momentum of this system just after the collision is 10 kg-m/s.