# Evil PHysics!!!!!!

posted by
**krystal** on
.

Hello,

I am having trouble with this problem:

During volcanic eruptions, chunks of solid rock can be blasted out of the volcano; these projectiles are called volcanic bombs.

a)At what initial speed would a bomb have to be ejected, at angle (sigma0=35 degrees) horizontal, from vent A in order to fall at the foot of the Volcano At B, at vertical distance h=3.30 km and horizontal distance d=9.40km? Ignore for the moment, the effects of air on the bomb's travel.

b) What would be the time of flight?

c)Would the effect of the air increase or decrease your answer in a?

Calculate the time of flight due to vertical velocity. Let vy be vertical velocity.

hfinal=hinitial+vy*time -1/2 g time^2

hfinal=0

hinitial=3300m

vy=Vsin35

Second equation:

Vcos35*time=9400m

V= 9400/(cos35*time)

Put that expression for V into the first equation, and solve for time. Note it is a second degree equation, so use the quadratic equation.

Thank you