Question

A planet is discovered that is the same size as Earth and has the same gravitational acceleration, but it has twice the mass. If you weigh 700 N on Earth, on the new planet you would weigh ____. (1 point)
350 N
700 N
1,400 N
2,800 N

Answer 1

gravitational acceleration is dependant on mass isnt it?

Answer 2

\[g = \frac{MG}{r^2}\]

Answer 3

yes g=G*M /R^2
it depends!!!!!!

Answer 4

im confused

Answer 5

once check ur quest @StealerGirly50

Answer 6

what?

Answer 7

If it has the same gravitational acceleration, the the weight is the same.
Though if it is the same size and twice the mass, then that can't be right.

Answer 8

ya so its not 700 N

Answer 9

would it be 350 N

Answer 10

or 1400 N

Answer 11

yes!!!!!!
the g value of a planet does depend on it's mass......
u said that g value is same so the body should weigh the same on both the planets.......
but in the next statement u said that the mass of the latter is twice to that of the former......so g changes ......the body no longer weigh the same on the two planets.......
contrast!!!!!!
so check ur quest once!!!!

Answer 12

That's what I'm saying: The problem statement doesn't make any sense. If it's the same size, but twice the mass, then that would double the force. But it said the acceleration is the same, so it can't be the same size for twice the mass or twice the mass for the same size.

Answer 13

@anusha.p i may be wrong but i think "g" for a planet is independent of its mass..
if you ask me,,ans should be 700N only..

Answer 14

weight = mg
m is constant
g is given to be constant
mass of planet doesnt play any role
so weight should be same..

Answer 15

@shubhamsrg do u have any idea of the formula for g!!!!!!
which is already there in the replies!!!!!

Answer 16

g is not independent of the mass of the planet. g is independent of the mass of any bodies near it since the force and mass are proportional.

Answer 17

so 700 N? this question is confusing me!!!

Answer 18

do you know what that M is in the formulla for g? thats not the planet's mass but the body's mass..you're just confusing yourself..

Answer 19

i think it's the planet's mass and r the radius of the planet itself!!!!

Answer 20

oh ok

Answer 21

wait im confused again what is the answer and how did you get that?

Answer 22

\[\frac{F_g=Gm_1m_2}{d^2}\]
If the planet is the same size, d is the same. If it has twice the mass, then the force doubles.
If the force doubles for the same body mass, then the acceleration of that body doubles too.

Answer 23

so the answer would be 700 N?

Answer 24

It's a poorly-worded question. The statements are inconsistent; no logical conclusion can be drawn from it. Make sure you copied down the question properly.

Answer 25

@StealerGirly50 no answers for this question:p

Answer 26

but there has to be an answer!

Answer 27

One of these three statements needs to be removed. They cannot occur together in this universe:
"it is the same size as Earth."
It has the same gravitational acceleration."
"It has twice the mass."

Answer 28

but that was the question that my teacher gave me :(

Answer 29

What do I pick?

Answer 30

do I just guess then?

Answer 31

u say deliberately "ur wrong...and ......

Answer 32

lol

Answer 33

Sorry. Here are some possibilities.
A) "it is the same size as Earth."
B) "It has the same gravitational acceleration."
C) "It has twice the mass."
Given (A) and (B), the mass of the planet is the same as Earth and the weight of any body on it would be the same as Earth.
Given (A) and (C), then the gravitational acceleration would be doubled, and the weight of any body on it would be doubled.
Given (B) and (C), the radius of the planet is smaller than Earth in proportion to keep the weight of any body near it the same as near Earth.

Answer 34

ahh D: ok thanks for helping everyone!!!!

Answer 35

If it were me, I'd either guess that it's a typo and most likely it's meant to be such that the gravitational acceleration is not the same, so the weight would double - or- I would simply write the truth: "This is an inconsistent collection of statements and no logical conclusion can be drawn from them."

Answer 36

ok thanks! no wonder I wasnt sure of the answer lol

Answer 37

hmmn,,leme try this :
F = weight = 700N =mg
m is mass of body
now F = GmM/r^2
=> g= GM/r^2
so yes its a planet's mass,,am sorry everyone..i'll go with
@CliffSedge in that case..hmmn..

Answer 38

ok thanks!

Answer 39

yeah, if you assume that "it is the same size as Earth," and "It has twice the mass" are true statements, then the weight would double on the new planet.