A ball is thrown in the air from a platform \( 4 \) meters above a river, at an initial velocity of \( 30 m / s \) , and its height above the river can be determined by the formula \( h ( t ) = - 4.9 t ^ { 2 } + 30 t + 4 \) .
a. Graph the function in DESMOS, then answer the following questions. Copy-paste the URL here.
b. When is the ball \( 7 m \) above the river? (two answers here, please)
c. Does it reach \( 50 m \) above the river?
d. When does it hit the water?