- #1
eroock
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There was an article in a German online magazine debunking the theories of moonlanding deniers. One of the issues was revolving around the question why the astronauts didn't seem to reach the heights expected when trying to jump off the ground.
The logic: Since moon's gravity is 1/6 of Earth's they should be jumping as high as 6 times of what they would be doing on earth. So if we assume them to jump 20 cm on Earth (suit included) they should effortlessly be doing 1 m on moon's surface which apparently wasn't happening.
Now the counter argument of the magazine was that these folks were confusing mass with gravity and gravity is not the only factor in the equation. While jumping you first have to overcome initia which refers to an objects mass and doesn't change whether you are staning on Earth or the moon. They didn't get deeper into the topic as it was a non-science acticle.
I wanted to know if there's some truth to it and researched the net. What I found is this formula to calculate the height of a jump:
Hmax = (Ftake-off power / (m * g) - 1) * hacceleration distance
with
F = 1,800 N
m = 160 kg
g = 9.81 (earth) and 1.62 (moon)
h = 0.3 m (downward bending of your knees)
I arrive at a ratio of even 1:10 when inserting g for Earth vs. moon. Unfortunately I cannot cite an English source for the equation above but I could go into more details if need be. For the time being, what is your general take on the mass/gravity impact on the experiment.
Thanks,
Edgar
The logic: Since moon's gravity is 1/6 of Earth's they should be jumping as high as 6 times of what they would be doing on earth. So if we assume them to jump 20 cm on Earth (suit included) they should effortlessly be doing 1 m on moon's surface which apparently wasn't happening.
Now the counter argument of the magazine was that these folks were confusing mass with gravity and gravity is not the only factor in the equation. While jumping you first have to overcome initia which refers to an objects mass and doesn't change whether you are staning on Earth or the moon. They didn't get deeper into the topic as it was a non-science acticle.
I wanted to know if there's some truth to it and researched the net. What I found is this formula to calculate the height of a jump:
Hmax = (Ftake-off power / (m * g) - 1) * hacceleration distance
with
F = 1,800 N
m = 160 kg
g = 9.81 (earth) and 1.62 (moon)
h = 0.3 m (downward bending of your knees)
I arrive at a ratio of even 1:10 when inserting g for Earth vs. moon. Unfortunately I cannot cite an English source for the equation above but I could go into more details if need be. For the time being, what is your general take on the mass/gravity impact on the experiment.
Thanks,
Edgar