Jim Vincent wrote:
Since mass is a constant factor on both sides of the equation, it
cancels out.


You need to compare one equation to the other. The masses are different. Yes,
for one glider, the masses cancel out, but not when comparing two different
masses, cetarus parabus.

You are confused. Can you explain what you mean by comparing one
equation to the other?

Let me try:

For glider one we have:

1/2*m1*v1^2=m1*g*h1

For glider two:

1/2*m2*v2^2=m2*g*h1

since the equations are quite similar for both gliders, of course ;-)
So comparing the two equations, you can now see that the mass,
surprisingly enough for you ;-, cancels out for both gliders.

I do hope you are not "helping" your kids doing their math-homework!

Christian 8-)