Answer:
← 16.57 ms⁻¹ if red ball initially travels →
Step-by-step explanation:
Theory
The law of conservation of linear momentum
The sum of linear momentum of a system under no external force remains constant.
In this scenario although different forces act on two vehicles by each other when we consider the total system of two cars no external unbalance force act on them. So we can apply this law.
As law says,
The sum of linear momentum before collision = The sum of linear momentum after collision.
Momentum = mass × velocity.
So we get, → 0.6×18 -1.4×26 = -0.6×4 + 1.4×v
where v = velocity of the blue ball,
The velocity of the red ball after collision and the velocity of the blue ball before collision is (-) because they are in ← direction
v = - 16.57 ms⁻¹ = ← 16.57 ms⁻¹