Technically, it should roll forever.
Not pushing yourself hard enough is the answer since your heart rate doesn't even hit your lower minimum.
Pushing yourself to the limit is at your max heart rate.
Just at the right spot is at your max heart rate.
Pushing yourself too hard is above your max heart rate.
Answer:
Proof is given below
Explanation:
The length contraction is given by Δx = Δx' *√(1 - v² / c²)
where Δx' is the proper length and is measured in the frame where the object is at rest
Since the y' and z' axes are perpendicular to the direction of motion there is no contraction
So if you let V0 = Δy' * Δz' *Δx'
and V = Δy * Δz * Δx = Δy'* Δz' * Δx
Then
V = V0 * √(1 - v² / c²)
