The earth's gravity causes objects on earth (you) to accelerate toward earth's center at approximately 9.8 m/s2, when an elevator accelerates toward the earth's center (down) some of the force that you feel from gravity (weight) is negated. This results in a feeling of weightlessness.
When the elevator accelerates upwards, it pushes you against the floor, increasing the normal force acting on you, making you feel heavier. When the elevator descends and decelerates, there is less normal force acting on you, so you feel lighter.
You feel weightless in a lift because the lift and everything inside it, including you, are accelerating downward at the same rate. This acceleration cancels out the force of gravity acting on you, making you feel weightless.
Gravity is a non-contact force that acts between two masses.
Yes, exactly. A useful way to think of an object in orbit is that it is falling towards Earth much like anything else but, because of its velocity and distance from earth, it keeps missing the ground. This seems slightly contradictory -- a weightless object under the pull of gravity -- but it isn't, really. Suppose you're in an elevator that's had its cables cut. (Heaven, forefend!). Gravity accelerates you and the elevator Earthward at exactly the same rate, so you feel like you're floating relative to the elevator, but you and the elevator are just falling at the same rate.
In a falling elevator, both the elevator and the object inside are accelerating downwards at the same rate under gravity. This creates the sensation of weightlessness, as the object is not experiencing any resistance or contact force from the elevator floor. However, gravity is still acting on the object, causing it to accelerate downwards at the same rate as the elevator.
When the elevator accelerates upwards, it pushes you against the floor, increasing the normal force acting on you, making you feel heavier. When the elevator descends and decelerates, there is less normal force acting on you, so you feel lighter.
You feel weightless in a lift because the lift and everything inside it, including you, are accelerating downward at the same rate. This acceleration cancels out the force of gravity acting on you, making you feel weightless.
It makes you dizzy, tired, feel weightless, slows down your thoughts and speech, addictive, spinning.
when the rockets stop firing, astronauts begin free fall (weightless).
Since the "normal force" is zero. (An example of a "normal force" is the upward force exerted by something as a reaction to the weight of an object which is on it.) A fuller answer: It's a bit like being in a fast moving elevator (a "lift"), but more extreme. When the elevator goes down, you feel a bit lighter. Gravity is pulling you down just the same, but it's not pulling you into the falling elevator floor quite so hard. On a space station you are in "free fall". You and the spacecraft and everything in it are "falling" at the same rate. The chair would not push up on you. That makes you feel "weightless". (Of course you don't fall to Earth because you also have a "forward velocity" too and that keeps you in orbit.) We sense gravity mainly by the fact that chairs, floors, etc resist the down force of our weight and push upwards on us. (Actually the Earth's gravity is a bit weaker in space. In the International Space station it's about 90% of the Earth's surface gravity. But that's not the reason you feel weightless.)
Gravity is a non-contact force that acts between two masses.
What you are feeling when an elevator stops is called deceleration. The elevator doesn't stop right away. If it did, your knees would buckle and you would fall down from the impact, so an elevator slows down like a car does just before it stops. What makes the sensation feel weird is there is no visual indication of this happening, so you may think it has stopped, but it is really just slowing down. When you get on an elevator and the doors close (hopefully), it has zero velocity. When it starts going up, it must accelerate momentarily. During this acceleration period, before the elevator reaches its constant traveling speed, your apparent weight increases. You can feel this force in your legs and feet. If the elevator suddenly stopped, you would keep going.You would continue going in an upward direction (because of your inertia), mainly because you are not buckled in or otherwise attached to the elevator. You would lose contact with the floor. During that unfortunate scenario, you would be momentarily weightless. But with nothing to propel you upward anymore, you would slow down because of the acceleration of gravity. On normally operating elevators, ones designed not to make people sick or terrify them, the deceleration is slight, so you don't lose contact with the floor. You may feel momentarily lighter (in fact, if you were standing on a bathroom scale, it would read lower during the deceleration as you approach your floor), but you would not feel weightless.
The astronaut, space ship and everything in it are all falling at the same speed (falling around the Earth is called ORBIT). If everything is falling at the same speed, they are effectively weightless. Its like falling in an elevator, if everything is falling at the same speed you will appear to be floating around the elevator. Until it reaches the basement.
Because of gravity
Helium is a gas that is weightless, odourless, and would make a barrel lighter.
They don't. The moon has gravity but not as much as earth so they feel that they have less weight. In outer space a person would feel weightless because no gravity that they could notice is acting upon them.
Yes, exactly. A useful way to think of an object in orbit is that it is falling towards Earth much like anything else but, because of its velocity and distance from earth, it keeps missing the ground. This seems slightly contradictory -- a weightless object under the pull of gravity -- but it isn't, really. Suppose you're in an elevator that's had its cables cut. (Heaven, forefend!). Gravity accelerates you and the elevator Earthward at exactly the same rate, so you feel like you're floating relative to the elevator, but you and the elevator are just falling at the same rate.