Calculating Mass and Weight on the Moon

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The astronaut can lift equipment weighing 392 N on Earth, which corresponds to a mass of 40 kg. On the Moon, the weight of this equipment is calculated to be 65 N due to the lower gravitational acceleration of 1.62 m/s². For part b, the maximum weight the astronaut can lift on the Moon is still 65 N, but the question emphasizes the need to consider the force exerted by the astronaut. To find the mass of the largest rock that can be lifted on the Moon, the astronaut's maximum lifting force of 392 N should be used in the equation W=mg, resulting in a different mass value than simply 40 kg. Understanding the distinction between the lifting force on Earth and the Moon is crucial for solving part b correctly.
reminiscent
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Homework Statement


The largest piece of equipment that an astronaut on Earth can lift has a weight of 392 N. On the Moon, the acceleration due to gravity is only 1.62 m/s^2.
a) What is the mass and weight of the same piece of equipment on the Moon?
b) What is the mass and weight of the largest rock the astronaut can lift on the Moon?

Homework Equations


W=mg

The Attempt at a Solution


For a), I found that the mass had to be 40kg on the Moon because mass does not change whether you're on Earth or on the Moon. For the weight, I just multiplied 40kg * 1.62 m/s^2 and found that the weight is 65 N.
For b), I am confused about what it is asking because isn't it the same answer as a)? If the largest equipment that the astronaut can handle is 40 kg, then a rock must be a max of 40 kg and wouldn't the weight also be 65 N? Quick help would be much appreciated.
 
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reminiscent said:

Homework Statement


The largest piece of equipment that an astronaut on Earth can lift has a weight of 392 N. On the Moon, the acceleration due to gravity is only 1.62 m/s^2.
a) What is the mass and weight of the same piece of equipment on the Moon?
b) What is the mass and weight of the largest rock the astronaut can lift on the Moon?

Homework Equations


W=mg

The Attempt at a Solution


For a), I found that the mass had to be 40kg on the Moon because mass does not change whether you're on Earth or on the Moon. For the weight, I just multiplied 40kg * 1.62 m/s^2 and found that the weight is 65 N.
For b), I am confused about what it is asking because isn't it the same answer as a)? If the largest equipment that the astronaut can handle is 40 kg, then a rock must be a max of 40 kg and wouldn't the weight also be 65 N? Quick help would be much appreciated.
There's a subtle difference between the answers to a) and b).

On earth, as astronaut's muscles provide the force necessary to lift a piece of machinery with a certain mass against the acceleration due to earth's gravity.

How much mass under the moon's acceleration due to gravity is equivalent to the maximum force which can be exerted by the astronaut?
 
SteamKing said:
There's a subtle difference between the answers to a) and b).

On earth, as astronaut's muscles provide the force necessary to lift a piece of machinery with a certain mass against the acceleration due to earth's gravity.

How much mass under the moon's acceleration due to gravity is equivalent to the maximum force which can be exerted by the astronaut?
I still don't understand... wouldn't that give me the same answer or do I need a different equation for part b) to find the answer?
 
SteamKing said:
There's a subtle difference between the answers to a) and b).

On earth, as astronaut's muscles provide the force necessary to lift a piece of machinery with a certain mass against the acceleration due to earth's gravity.

How much mass under the moon's acceleration due to gravity is equivalent to the maximum force which can be exerted by the astronaut?
I kept reading your reply and this is my understanding:
So the maximum force which can be exerted by the astronaut is 392 N, correct? So, I just have to plug in 392 N into W=mg in terms of the moon's acceleration to find the mass?
 
reminiscent said:
I kept reading your reply and this is my understanding:
So the maximum force which can be exerted by the astronaut is 392 N, correct? So, I just have to plug in 392 N into W=mg in terms of the moon's acceleration to find the mass?
Yes.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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