goring
Lv 6
goring asked in Science & MathematicsPhysics · 2 years ago

# if we are sitting on a bench are we really accelerating toward the center of the earth do we really feel the motion?

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• 2 years ago

Yes, in order to stay on the surface of the earth instead of flying off into space, you are constantly being moved in a 24 hour circle. In "sitting still" you are actually folllowing a curved path around the earth's axis.

This requires constantly changing direction, which is an acceleration.

Can you feel it? Well you can feel your weight. You can feel the gravitational pull of the earth. Around 1% of your weight is involved in moving you in that circle. Can you feel that 1% of your weight? Probably not. If I suddenly changed your weight by 1% you probably wouldn't notice it. But it can be measured.

• goring
Lv 6
2 years agoReport

Basically a force does not exist without acceleration

• cosmo
Lv 7
2 years ago

If you are sitting on a bench, you are really being accelerated away from the center of the Earth. If you were in freefall, you would move toward the center of the Earth --- acceleration keeps you stationary.

• 2 years ago

As the Earth rotates, you are moving in a circle and are undergoing a centripetal acceleration. You cannot “feel” motion. You only feel forces which act on your body. In this case gravity pulling you down and the bench holding you up. The net force is down.

• ?
Lv 4
2 years ago

Remember:

F = MA

Note, there is no velocity term in that equation.

Relative to the earth and the bench you are motionless, so the acceleration ( of gravity) is felt as the FORCE on your butt by the bench that prevents you falling to the center of the earth.

• neb
Lv 7
2 years ago

If you are sitting on a bench you are in a non-inertial (accelerated) reference frame. If you were in freefall (not on the bench) you would be in a locally inertial (non-accelerated frame).

So, why does this counter-intuitive notion exist? When in freefall, you are traveling a geodesic - the shortest distance between two points in spacetime. This is a path in which you feel no acceleration. When you are sitting on a bench, the bench is preventing you from ‘traveling’ on the geodesic so that deviation from the geodesic puts you in a non-inertial reference frame.

• ?
Lv 6
2 years ago

Not practically, no.

Technically, I can see an argument that since you are on Earth and the planet is orbiting the sun and rotating then actually you are constantly changing direction and thus are accelerating, but definitely not noticeably.

Edit: Nevermind, read the question wrong.

• Kieth
Lv 7
2 years ago

More babbling science, just like the big bang and travel half the distance theories. You can sit on a park bench for a month and never get past the grass, combustion doesn't create life, and if you travel half way to Amsterdam each day, you will get there. One half of an inch from Copenhagen? Trust me, you're in Amsterdam.

• Sam
Lv 4
2 years ago

No and no.