A trolley weighing 2 kg is at rest on a trolley weighing 4 kg at a speed of 3 m / s and engages with the first.

A trolley weighing 2 kg is at rest on a trolley weighing 4 kg at a speed of 3 m / s and engages with the first. What is the speed of the carts after interaction.

To solve the problem, we need to recall the law of conservation of inertia p1 = p2 where
p1 is inertia before interaction
p2 is inertia after interaction
To find the speed, we first find p1
p1 = 4 * 3 = 12 (kg * m / s)
Since p1 = p2, we equate and find the speed, but we will use not 2 or 4 kg, but 6 kg, because they are linked and together will have a mass of 6 kg
12 = 6 * V
Where v is
V = 12/6 = 2 (m / s)
Answer: V = 2 (m / s)