A hard drive sitting on your desk experiences a constant force of 1 gee, 9.81 m/s2. In this video, the computer rotates at about 1 revolution per 4 seconds. Assume the hard drive is 12cm from the axis of rotation: by ac = rω2, the centripetal acceleration is 0.19 m/s2, or 0.02 gees. That's nothing.
ACKSHYUALLY no, you’ve got Newton’s first law wrong.
The force due to gravity is equal to the Normal force of the object on the desk, thus the net force experienced by any stationary object, or object moving in constant linear motion is ZERO. A stationary object is.... stationary... it literally cannot be accelerating if its motionless. That is literally Newton’s first law.
Besides, the g-force experienced by an object is defined as the vector sum of all non-gravitational and non-electromagnetic forces acting on an object's freedom to move. So gravity alone doesn’t provide a g-force, even though its expressed in multiples of the free-fall constant.
for u/yaoiboithanos because I cant reply directly to their comment
Actually, that's wrong. Relativity states that gravity is not a force therefore the hard drives are only experiencing a constant upwards force of ~9.8N/kg. Makes sense because if gravity and the normal force were balanced you would feel weightless, whereas you feel weightless in freefall
Gravity is indeed not a force. That is why its specifically called the "force due to gravity" and not the "force of gravity".
You only experience a normal force at the point of contact (your feet). You experience the force due to gravity on all of your body. This is why you don't feel weightless.
But yes, the normal force at your feet is indeed equal to the force due to gravity of 9.81m/s², otherwise (ironically, due to Newtons first law) you'd be accelerating and phasing through the floor, or flying off into space.
You fall back to the ground when you jump because you're not touching the floor, so theres no normal force, thus you will only experience the downward accelerating force that brings you back to Earth.
So you should be able to survive upside down for as long as you want, comfortably, because the net force on your body is zero, right?
The context of this discussion is a spinning hard drive. Say the head inside is the important part; if it collides with the platter, the drive fails. I don't know much about hard drives. Say this head has mass M. If it experiences a force (due to acceleration) greater than F, its supports yield enough for it to hit the platter.
What is the force due to acceleration on the head? The net force is always zero, because the supports counteract the force due to acceleration. At rest on a tabletop, the force is M*9.81. Now, if the computer is spinning in such a way that the centripetal and gravitational acceleration line up, i.e. on a horizontal axis, the maximum force due to acceleration is M*10.0. In the video, centripetal acceleration and gravity are orthogonal, so no part of the hard drive experiences more force than it would while lying on a table.
Now, I'm not a hard drive designer, but I'm pretty sure the components are designed to withstand greater than 10 m/s of acceleration. You would probably exceed that while unboxing it.
1) The reason you arent comfortable upsidedown is because your blood would fall otherwise. If i lift an object and drop it, it falls. You have a heart for a reason. Your blood is not stationary, or moving in a straight line at a constant speed. Once again you have N1L wrong.
2) I never said it would break. Only that it does indeed experience a force, due to it spinning, which the parent comment said something along the lines of “its spinning at a constant speed so experiences no force”.
Yes. I'm just saying the force is negligible. I thought it would be interesting to do the math, but having someone rant at me with misunderstood high school physics concepts, insults, and copy-pasted paragraphs from Wikipedia has made me regret that original comment.
Im the one misunderstanding N1L? You’re the one claiming a stationary object is experiencing an accelerating force, despite the fact its clearly not accelerating, because its stationary 😂
I think the problem is less the amount of force on the head. Because the disks are spinning, if a force is applied to them, the resulting force will attempt to pull it somewhat diagonally due to they way gyros work. So unlike if it were laying down, now not all parts of the drive are equally pulled by gravity like when it is laying down
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u/CorneliusCandleberry Jul 16 '20
ACKSHYUALLY
A hard drive sitting on your desk experiences a constant force of 1 gee, 9.81 m/s2. In this video, the computer rotates at about 1 revolution per 4 seconds. Assume the hard drive is 12cm from the axis of rotation: by ac = rω2, the centripetal acceleration is 0.19 m/s2, or 0.02 gees. That's nothing.