2 ms·
Note: This is completely wrong. The yard stick has a normal force vector from the hand passing through its center of mass. It doesn't start to rotate unless an
by zardo 11y ago
Note: This is completely wrong.
The yard stick has a normal force vector from the hand passing through its center of mass. It doesn't start to rotate unless an outside force is applied.
Of course in the real world it requires active control because the most minute misalignment causes a feedback that moves it further out of alignment. The rocket is exactly the same, if the thrust vector is not directly between the center of mass of the rocket, and the Earth, it starts to tip over.
If it were a stable system, misalignment would push the system back into alignment.
- DenisM 11y agoThe engines are attached to the rocket. Unless the engines are deliberately twisted, the thrust vector is going through the center of mass at all times, regardless of tilt. So if a rocket tilts in flight, it will not tilt further and it will not fall back. The yard stick, if tilted, will tilt further still and eventually fall, unless caught.
- jakub_h 11y agoIt's not the case with a rocket, unless you're flying forward with a liquid propellant rocket and the fuel tanks are almost empty so that the center of mass is significantly behind the center of drag (and the atmosphere is appreciable). That is an inverted pendulum situation. Outside of atmosphere and/or at low velocities, there's no instability of this kind, and "flying backwards" (=landing) makes the rocket actually auto-stable (like with a dart), even if the time constants may not necessarily be meaningful for useful control here.