Finding weights on other planets

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In summary, on the moon, where g is 2.64 times that of Earth, the mass of a bag of sugar is 3.71 Newton. On Jupiter, where g is 2.64 times that of Earth, the mass of a bag of sugar is 58.7 Newton.
  • #1
themadperseid
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Finding weights on other planets URGENT

yeah, here comes a homework problem my class had that both me and my friends couldn't get. please help us :bugeye:

A bag of sugar weighs 5.00 lb on earth. what should it weigh in Newtons on the moon, where the free-fall acceleration is 1/6 that of earth. repeat for jupiter, where g is 2.64 times that on earth. find the mass of the bag of sugar in kilograms at each of the three locations.

The book answer is 3.71N, 58.7M, 2.27Kg

What just happened. can anyone walk me through this. My e-mail is madperseid@yahoo.com, and my aim sn is themadperseid. Thanks
 
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  • #2
Weight is mg, where m is the mass and g is the gravitational acceleration.

For example, if an object has mass 5 kilograms, and is on a planet with g=10 m/s^2, then it weighs 50 Newton.

The problem is getting you to think about the difference between mass (the amount of stuff in an object) and weight (the force of gravity on an object).

You need to know that the freefall acceleration on Earth is 9.8 m/s^2. You'll also need to convert pounds to Newtons. (I don't know the conversion factor for that, since I live in a country which uses sensible units. I think pounds are a unit of weight, not mass, though.)
 
  • #3
James R said:
I think pounds are a unit of weight, not mass, though.)

Depends on the system. In one version, pounds are force and mass is in poundals. In a more common system, there is the pound-force and the pound-mass: one pound-mass weighs one pound-force under one standard g.

And people say those aren't sensible units! Hmph.
 
  • #4
riru, i hope u read this this morning. IVE GOT IT. ok, so here goes

w=mg
thus 5lbs=m*(9.8m/s^2)
since 5lbs is not ci units, convert, using the ratio that 1n=.2248lb
the conversion turns 5 lbs into 22.24n
22.24n=m*(9.8m/s^2)
due to the nature of n (kg*m/s^2), you can divide out g [m/s^2], leaving only the kg mass of the bag on Earth (22.7 kg)
then, since w=mg
you merely substitute the mass in, and multiply the gravity by the given ratio
example for moon (2.27kg*((9.8)*(1/6)))=3.7N
For the Jupiter one, you do the same, and multiply the gravity by the given ratio
example for Jupiter (2.27kg*((9.8)*(2.64)))=58.7n
 
  • #5
I didn't bother to check the arithmetic, but you've got the concept down. Bravo!
 

Question 1: How is weight measured on other planets?

Weight is measured by the gravitational force exerted on an object by the planet. This force is dependent on the mass of the planet and the distance between the object and the planet's center.

Question 2: Are weights on other planets the same as on Earth?

No, weights on other planets are not the same as on Earth. This is because the gravitational force varies depending on the mass and size of the planet.

Question 3: How does weight differ on planets with different gravities?

Weight on planets with stronger gravity will be greater, while weight on planets with weaker gravity will be less. This is because the gravitational force is stronger on planets with higher mass and density.

Question 4: Can humans survive on planets with different gravities?

It depends on the strength of the gravitational force. Humans are adapted to Earth's gravity and may experience health issues and difficulties in movement on planets with significantly different gravities.

Question 5: How does weight affect objects on other planets?

The weight of an object on a planet will determine how much force it exerts on the planet's surface. Objects with greater weight will exert more force, while objects with less weight will exert less force.

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