Gravity and stuff on planets???

Question

I have this one programming assignment in my intro2cs class and im programming a weight on planets converter in c++ and im getting a little mixed up with the weight and mass stuff. I had to do this in my physical science class a while ago cept i dont remember. im just wondering what would the formulas be for the following planets. (The variable being kilograms because I have trouble with newtons)
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Neptune
Pluto

I was kinda confused cuz I had remembered in science class we divided the gravity on earth by 9.8 but in other websites it
says that we should just multiply by 1. Im reeeely confused and if i could just get the basic formulas ill be happy.

Thanks

Answer 1

9.8 is the pull of gravity on earth, so if you are looking for weight in newtons on earth then that is kilograms * 9.8
the 9.8 would be a different number for different planets, the way you calculate that is using this equation
F = (Gm)/r
F is the number that you would use instead of 9.8 for different planets
G is the gravitational constant = 6.67*10^-11
m is the mass of the planet
r is the radius of the planet
your final weight in newtons would be F times the kilograms
which you can then convert to pounds by multipying that by 0.22481

Answer 2

This is a VERY good question! It shows that you have a very good scientific mind and you are really thinking about what you read and what you see on tv, etc. One way is we use physics. When the light of a star passes a planet, some of that light travels thru that planet's atmosphere. Light passing thru an atmosphere is changed as it passes thru, just like sunlight is changed when it passes thru a prism. We (scientists) have created very sophisticated telescopes that are now out in space orbiting the earth and looking specifically for planets orbiting distant stars. These telescopes are looking at visible light and UV and IR and X-rays and probably a bunch of other things. Analyzing how that star's light changes around that planet tell us many things. Someone who is a practicing astrophysicist can probably provide many more details, including the names of those orbiting telescopes. With that name, you can go to NASA's website and find even more info. It is fascinating that we can learn as much as we do over such vast distances.

Answer 3

Maybe you should take an intro grammer course because yours is awful.
You need factors for each planet that will convert mass (which is for most purposes, a constant) into force, which is given by F= ma, where a is the accleration constant. On earth, as you noted, it is 9.8 m/sec^2, and each unit of mass converts to a force in newtons.
You can look up the corresponding factors for other planets. Off the top of my head, for Mercury, it is about (relative to earth) 0.4, for Venus 0.9, for Mars 0.4, for Jupiter, 2.65, for Saturn, 0.9, for Uranus and Neptune, about 1. Pluto was demoted from being a planet.

Answer 4

The equation for g on a planet of mass M and radius R is

g = G*M/R, where G is the universal constant of gravitiation.

Wikipedia can provide you with the figures for all the planets.

Remember that a body's mass is always the same, regardless of the planet that it is on. The weight however will vary, because the acceleration due to gravity will also vary.
(weight = mass*g)

Answer 5

Use the "Gravity" column in the source to compute the number for each planet. Earth is listed as "1", meaning 1 times 9.8. Mars, for example, is listed as 0.38, meaning 0.38 times 9.8.