0
$\begingroup$

When we use an automatic screwdriver ie: screwdrilling machine, we set the controls of the machine in such a way so as to rotate the drill bit at a certain fixed speed.

But the point around which I can't wrap my head around is that if the screwdrilling machine is providing torque for the drill bit to rotate there has got to be an angular acceleration of the drill bit because of the equation $ T = I \alpha $ .

If there is angular acceleration then it ought to speed up it's rotation ( angular velocity) over time. Then why does the drillbit seem to be moving at a constant angular velocity.

$\endgroup$
  • $\begingroup$ Don't forget about friction $\endgroup$ – Triatticus Feb 11 at 5:33
  • $\begingroup$ Closely related recent question: physics.stackexchange.com/questions/530198/… $\endgroup$ – G. Smith Feb 11 at 5:58
  • $\begingroup$ Consider the situation as if the screwdrilling machine with the drillbit is spun in mid air. Because then also we observe that the drill bit spins at a constant angular velocity $\endgroup$ – user198885 Feb 11 at 6:07
  • $\begingroup$ @G.Smith I read those answers but I think that the question that even though an $\alpha$ exists why is there a constant angular velocity , still remains unanswered $\endgroup$ – user198885 Feb 11 at 6:09
  • $\begingroup$ Yes but there is internal friction between the gears and other internals $\endgroup$ – Triatticus Feb 11 at 6:10
0
$\begingroup$

The screw drilling machine has an automatic speed controller built in to it. When you set the speed you want, the control system maintains that speed for you by varying the voltage to the drive motor, and monitoring how fast it is turning at all times. In this regard, it's like the cruise control in your car.

| cite | improve this answer | |
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.