Show that Newton's 2nd Law is *Not* valid in a reference frame

[Tonia]

Homework Statement

Show that Newton's Second Law is NOT valid in a reference frame moving past the laboratory frame of problem 1 with a constant acceleration?
Problem 1: In a laboratory frame of reference, an observer notes that Newton's Second Law is valid. Show that it is also valid for an observer moving at a constant speed, small compared with the speed of light, relative to the laboratory frame.
dx^1/dt = dx/dt-v
d^2x^1/dt^2= d^2x/dt^2
force new = force old
acceleration = d^2x/dt^2 and if v is constant = dv/dt = 0

Homework Equations

F = ma

The Attempt at a Solution

I am not sure how to solve it

 

[Simon Bridge]

You don't have to be sure of the approach to use the approach.
Try showing that the force on the object is not equal to it's mass multiplied by it's acceleration.