A ball is thrown into the air. Its height (in feet) $t$ seconds later is given by

$h(t) = 80 t - 16t^2$
Based on the two equivalent forms of the function $h(t) = 80 t - 16 t^2 = t \cdot (80 - 16 t)$, answer the following questions:

a) What is the height of the ball 1 second after it has been thrown? (include units in your answer)

b) After how many seconds does the ball hit the ground? (include units in your answer)

c) At what time(s) is the ball 30 feet above the ground? If there is more than one answer, give your answer as a comma separated list of values. Note that you do not have to include units in this answer.
After seconds