Between the top of the first and the top of the second loop, the coaster has lost potential energy = mgh, where h = 22.2 - 15 = 7.2m
This energy would have converted to Kinetic. Write out an equation and the masses will cancel out. Does that hint help you to find the solution? If not, I will give you another hint.
Simply because the baseball is much lighter than the bowling ball. Making it easier for the average adult to throw the baseball farther than the bowling ball
a) 
, 
The work done by the student in each trial is equal to the gravitational potential energy gained by the student:
where
m = 68 kg is the mass of the student
g = 9.8 m/s^2 is the acceleration of gravity
is the gain in height of the student
For the first student, 
, so the work done is
The second student runs up to the same height (3.5 m), so the work done by the second student is the same:
2) 
, 
The power exerted by each student is given by
where
W is the work done
t is the time taken
For the first student, and 
, so the power exerted is
For the second student, 
and 
, so the power exerted is
R2^ 2 / R1 ^2 = g1 / g2 = 38
<span>R2 = R1 x √38 = 6.1644* R1 </span>
<span>R2 = 6.1644 x 6378 000 = 39316632.5 m</span>
