Question

A golfer drives a ball with a velocity of 42 m/s at an angle of 45 degrees above the horizontal. What is the maximum height (in meters) of the ball above the level fairway?

Answer 1

figure vertical velocity intial: 42sin45

then, knowing the vertical velocity at the peak is zero...
Vf^2=Vi^2+2gd

figure d

Answer 2

so does that mean vf is zero, vi is 29.69848481, and g is 9.8

Answer 3

g is -9.8m/s^2, so the answer d will be postive, or it should be. Your carrying all those digits on V is nonsense. You are restricted to two significant digits, given the info in the problem.