PDA

View Full Version : simple question for you


gnickg
Sep26-03, 09:18 AM
I am no science or physics major but this is my first quiz. I have this problem:
How much force must be applied to accelerate a 10,000-kg space shuttle to counter the earth's gravitational acceleration of 9.8 meters per second square?
I took 9.8m/s^2 * 10,000 for 98,000 newtons.
Is that correct?
Your help is much appreciated!
gnickg

russ_watters
Sep26-03, 09:40 AM
Yep.

Followup: the space shuttle accelerates at roughly 3g's at liftoff. What's the force? (careful, its a bit of a trick question)

Chi Meson
Sep26-03, 02:28 PM
Originally posted by gnickg
I am no science or physics major but this is my first quiz. I have this problem:
How much force must be applied to accelerate a 10,000-kg space shuttle to counter the earth's gravitational acceleration of 9.8 meters per second square?
I took 9.8m/s^2 * 10,000 for 98,000 newtons.
Is that correct?
Your help is much appreciated!
gnickg

So far so good. Here's a conceptual helping hand: "g" is always called "acceleration due to gravity," but that's a misnomer (wrong name). An object only has an acceleration equal to "g" when it is in free fall in a vaccuum.

Think of "g" as the gravitational field intensity, and no matter what is happening, the gravitational force on something will be "mg" . A lot of people get confused by multiplying mass times an "acceleration" when the darn thing isn't going anywhere!

Hope this is helpful.

schwarzchildradius
Sep27-03, 03:57 AM
It's an acceleration vector field, equivalent to accelerating at 9.8 m/s2 away from a massless earth. By the equivalence principle, the difference between being stationary in a vector field and accelerating is an illusion.
gnickg this problem is about finding where forces balance, balanced forces are equal to each other- you solved it the right way.

gnickg
Sep30-03, 01:06 PM
Thanks everyone for your help on my physics question. I got an "A"...!