Reference no: EM132080241

A ball is dropped from the top of a building. The height, y, of the ball above the ground (in feet) is given as a function of time, t, (in seconds) by

y=1920-16t?2??

(a) Find the velocity of the ball at time t. v(t)= ___?___

What is the sign of the velocity? (choose: positive or negative)

Why is this expected? This is reasonable because the height is: (choose: increasing, decreasing, or constant)

(b) When does the ball hit the ground, and how fast is it going at that time? Give your answer in feet per second and in miles per hour . (1 ft/sec = 15/22 mph)

Round your answers to two decimal places.

t= ___?___

v(t)= ___?___ feet per second

v(t) = ___?____ miles per hour