As Redbelly98 already suggested, it's really quite logical (what isn't in physics once you see it) and has everything to do with the work done.
Let's suppose equal accelerations, whatever the reference frame.
a=\frac{\Delta v}{\Delta t}
That means that for the same change in speed we...
No need. Just take a little time to realize that kinetic energy is calculated by ½mv² , not by
1/2 m(\Delta v)^2
Then, as v depends on your frame of reference, kinetic energy unavoidably also depends on your frame of reference. No point in changing your frame of reference halfway through an...