Question

A marble is dropped from the top of the empire state building.
a. Determine the position and velocity functions for the marble
b. What is the average velocity for the first 3 seconds of flight?
c. Whatisthespeedofthemarblewhent=0? t=3? t=6?
d. How long does a person looking up from the ground have to evade the marble? e. What is the velocity of the marble hitting the ground?

Answer 1

a = g = -9.81 m/s^2

v = -gt = -9.81 t

h = Hi - (1/2) g t^2 = Hi - 4.9 t^2

b)
h at t = 0 = Hi
h at t = 3 = Hi-4.9 t^2 = Hi - 44.1 m/s

average = (-44.1)/3 = - 14.7 m/s

c) at 0 v = 0
at 3 v = -9.81*3 = -29.4 m/s
at 6 v = -9.81*6 = -58.9 m/s

d) well I am not about to Google Hi
Hi = 4.9 t^2
v = -9.81 t

Answer 2

if you were supposed to use feet instead of meters as your other problem that I just saw, use 32 ft/s^2 for g not 9.81 m/s^2