physics
posted by Jen on .
A model rocket leaves the ground, heading straight up at 47 m/s.
(a) What is its maximum altitude?
m
What are its speed and altitude at each of the following times?
(b) 1 s
m/s
m
(c) 4 s
m/s
m
(d) 8 s
m/s
m

a. When h = hmax, Vf = 0.
(Vf)^2 = (Vo)^2 + 2gh = 0,
(47)^2 + 2(9.8)h = 0,
2209  19.6h = 0,
19.6h = 2209,
h = 2209 / 19.6 = 112.7m.
b. V = Vo + gt,
V = 47 + (9.8)1,
V = 47  9.8 = 37.2m/s.
h = Vo*t + 0.5gt^2,
h = 47*1 + 0.5(9.8)1^2,
h = 47  4.9 = 42.1m.
c. Same procedure as b except t = 4s.
d. Same procedure as b, and c except
t = 8s and g = +9.8.
NOTE: g = + 9.8 for all values of t above 4.8 because the rocket is falling.
seconds because the rocket is