Answer to Question #126424 in Mechanics | Relativity for Kashish

Question

The inertia of an object is m measured when the object is at rest in the Earth reference frame. According to Galilean relativity, what is its inertia measured by an observer moving past the object with a constant velocity v⃗ in the positive x direction?
Express your answer in terms of some or all of the variables m and v⃗ . What is the object's momentum according to this observer?

Answer 1

Answer: If the observer moves relative to the Earth with a constant velocity v, then the velocity of a stationary object relative to the observer is equal to -v.

According to the observer, the momentum of the object is equal to p = -mv.