Question

A sniper fires a bullet at 120 m/s at 30° above the horizontal from the roof top of a 35 m high parking garage. If the bullet strikes the level ground beside the parking garage:

a) How long was the bullet in the air?

b) How far from the base of the parking garage did the bullet land?

c) At what angle did the bullet land?

Answer 1

Vo = 120m/s[30o]
Xo = 120*cos30 = 103.9 m/s.
Yo = 120*sin30 = 60 m/s.

a. Y = Yo * g*Tr = 0
Tr=-Yo/g = -60/-9.8 = 6.12 s. = Rise time.

h = ho + (Y^2-Yo^2)/2g
h = 35 + (0-(60^2))/-19.6 = 218.7 m.
Above gnd.

h = 0.5g*t^2 = 218.7
4.9t^2 = 218.7
t^2 = 44.63
Tf = 6.68 s. = Fall time.

Tr+Tf = 6.12 + 6.68 = 12.8 s. = Time in
air.

b. d = Xo*(Tr+Tf) = 103.9m/s * 12.8s =
1330 m.

c. Y^2 = Yo^2 + 2g*h
Y^2 = 0 + 19.6*218.7 = 4286.52
Y = 65.5 m/s.

Tan A = Y/Xo = 65.5/103.9 = 0.63041
A = 32.2o

Answer 2

TYPO: Change Y = Yo*g*Tr = 0 to
Y = Yo + g*Tr = 0

Answer 3

Thanks Henry,

You're a good guy!

Answer 4

honestly henry u is smart and loyal love ya

Answer 5

What is Y supposed to be?

Answer 6

Y^2 = Yo^2 + 2g*h

In that formula, what is Y??

I know Yo is vertical velocity, g is gravity and h is height but what is Y?

Answer 7

DAMN! they teaching kids about rifle basics in school?!?!?! WOW, just wow.