7 jack accidentally dropped his cellphone from a hot air balloon that

Question

7. Jack accidentally dropped his cellphone from a hot air balloon that was 128 feet from the
ground. The distance, (s), his phone is from the ground is described by the function:
s = -16t² + 144. Time (t), is measured in seconds.
Find the following: (4 points each). Be sure to include units in your answers!
a. Determine the distance of the phone from the ground after 1.8 seconds.
b. What is the velocity of the phone at 0.75 seconds?
C. When does the phone hit the ground?
d. What is the acceleration of the phone at 0.5 seconds?