|Why do we feel as if we weight the same on Venus as we do on Earth? Do we weight the same in both places?|
|Question Date: 2019-09-06|
Great question! What usually gets people confused about this topic is the difference between the mass of an object (like me, you, a rock, or a car) and the weight of that object.
Mass is a constant property, meaning that I could travel all over the solar system and still have the same mass at each planet. The only way for me to change the mass of something like a car is to take things out of it, like if I removed all of the seats inside, to make it have less mass. I could also fill the car with groceries to make it have more mass, but moving the car to different planets won't change its mass unless we put things on it or take things off of it as we travel between planets.
The difference with your weight is how its calculated. While mass is a property of me or you or the car, weight is actually a force that is acting on me, you, and the car.
Weight is your mass times the gravitational acceleration of the Earth, and it has the units of force. Just like how you would feel a force on your hand if you pushed against a wall, the earth is pulling you towards it so you feel your weight on your feet (or on your legs if you're sitting down).
Now that we know the difference between your mass and your weight, we need to know what would be different between Earth and Venus. We know that weight is a force, and force is calculated by multiplying a mass by acceleration. Mass is a property that belongs to you, so that can't change between here and Venus. That leaves us with acceleration as what is different between Earth and Venus, specifically the gravitational acceleration of the planets.
Earth has a gravitational acceleration of 9.81 meters/second2, and Venus has a gravitational acceleration of 8.87 meters/second2, which is less than Earth's.
So, would you weigh the same on Earth and Venus? You certainly would have the same mass, but you would actually weigh less on Venus because the gravitational acceleration is less on that planet.
Have a great weekend!
Your weight on a planet is equal to your mass which is the same on both time GM/R2 where G is a constant the same on Venus and Earth. M is the mass and R is the radius of the planet… so Venus has a smaller value of M/R2 than Earth so you weigh a little less on Venus than on Earth … but the difference is small about 10 %.
If we step onto the surface of Venus, we would feel that we weigh about the same as on Earth, but a little less.
This is because the gravity of Venus is similar to the gravity of Earth. On both planets, we would have the same mass, in other words, the same amount of "stuff" that make up our bodies. However, we will not weigh the same because weight does not directly measure mass. It also measures the gravity of the thing on which we're standing. Therefore, even though we have the same mass on both Earth and Venus -- the same amount of "stuff" -- we will not weigh quite the same, but kind of close. We would weigh less on Venus than we do on Earth.
Weight is actually a measure of force of attraction between you and another object, so it depends on that object’s gravity!
So we would not weight the same on Venus as on Earth. Venus is slightly less massive than Earth, which means its gravitational pull is slightly less. As a result, you would actually weigh less on Venus than Earth! There is a cool website where you can see how much you would weigh on all the different planets, as well as some stars and moons. Try putting in your weight and seeing how much it changes! here.
Venusian gravity is about 9/10 as strong on the surface as Earthly gravity. Thus, if you weigh 100 pounds on Earth, you would weigh about 90 pounds on Venus.
The strength of gravity on the surface of a planet or moon depends on the mass of the planet or moon (more mass means more gravity), and on the size of the planet or moon (the farther you are from the center, the less gravity). By the time you are a high school freshman, you should know enough math (algebra) to be able to calculate how strong the gravity will be on the surface of a planet, given its density and its size.
Earth and Venus are almost the same size (Venus is slightly smaller), and almost the same mass (Venus is slightly less massive). This is why the gravitational force at the surfaces of these two planets are almost the same. All of the other planets and moons in the solar system are either much larger than Earth or much smaller, which is why they have such different surface gravity.
The idea of weight on different planets is a fun one to think about, and it's a good example that can teach us about how gravity works. The first thing we need to think about to answer the question is the idea of weight versus mass. Weight is the one we're more familiar with: when you pick something up, you can feel it wanting to move toward the ground. Mass is a little different. When we say something has a certain mass, we mean that we know it has a certain amount of stuff in it. This might seem like a funny definition, but using it we can think about weight a little differently. Weight is the amount of force that gravity puts on a certain amount of stuff. Mass is just the amount of stuff itself.
An important thing to keep in mind is that while weight changes depending on where you are, mass does not change. Just like when you jump on a trampoline and feel weightless at the top of your jump, that doesn't mean you're made of any less stuff! Your mass is the same, it's the forces on you that have changed. The force from the trampoline canceled out some of the force from gravity, so you feel like you weigh less, but you certainly haven't lost any mass.
This leads us to the question of weighing ourselves on Earth and Venus. Another thing to know about gravity is that it gets stronger the more massive something is. That's why planets (which are really heavy) have such huge gravitational forces, and the two of us (which are not so heavy compared to planets) have tiny, imperceptible gravitational forces. So what we can say about gravity on different planets is that the more mass a planet has, the stronger gravity will pull objects toward that planet. Since Earth is a little bit bigger than Venus, Earth has stronger gravity than Venus does. This means that, even though you have the same amount of mass in both places, gravity will pull you harder on Earth than it will on Venus. This means you will feel like you weigh more on Earth, and weigh less on Venus!
Yes, if it were possible to stand on the surface of Venus, you would weigh about the same as you do on Earth. The strength of gravity, the force that keeps us on the ground, is about the same on Venus as it is on Earth. On the moon, gravity is much weaker, so you will weigh less there.
For a more detailed explanation, we have to think about weight and mass. Mass is the amount of matter, or “stuff,” that makes up an object. Your mass is always constant, no matter what planet you go to. Your weight tells you the force that gravity is exerting on you (this is what a scale measures). The force of gravity depends on your mass AND the mass of the planet you stand on.
Earth and Venus are about the same size, so they have about the same mass. If you go to Venus, your mass hasn’t changed, and the planet mass is almost the same as earth- so the force of gravity on you (AKA your weight) will be the same. The moon has a smaller mass than the earth, so if you go there, the gravitational force will be smaller, and you will weigh less (although your mass is still the same).
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