Answer:
h should become four times.
Explanation:
The speed at the bottom depends only on the vertical height difference from the top ... if there is no friction ... then the path you take from top to bottom doesn't matter in any way, only the difference in height between the two
mgh at top = 1/2 mv^2 at bottom, so that v=sqrt[2gh]
You see, the final velocity, v, depends on the square root of h, so double v, quadruple h, or four times higher
