The motor of an engine is rotating about its axis with angular velocity of 120 r.p.m. it comes to rest in 10s, after being switched off. Assuming constant deceleration, calculate the number of revolutions made by it before coming to rest.

The motor of an engine is rotating about its axis with angular velocit

1.	The motor of an engine is rotating about its axis with angular velocity of 120 r.p.m. it comes to rest in 10s, after being switched off. Assuming constant deceleration, calculate the number of revolutions made by it before coming to rest.
Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :Here, `omega_(0)=120` r.p.m `=<a href="https://interviewquestions.tuteehub.com/tag/2-283658" style="font-weight:bold;" target="_blank" title="Click to know more about 2">2</a>` r.p.s `=4pirads^(-<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>)` <br/> `omega=0` and `t=10s` `omega=omega_(0)+at` <br/> `0=4pi+axx10` or `a=-0.4pirads^(-2)` <br/> Also, the angle covered by the motor, <br/> `theta=omega_(0)t+(1)/(2)at^(2)` <br/> `:. theta=4pixx10+(1)/(2)xx(-0.4pi)xx10^(2)=40pi-<a href="https://interviewquestions.tuteehub.com/tag/20pi-1822115" style="font-weight:bold;" target="_blank" title="Click to know more about 20PI">20PI</a>` <br/> `=20pi`rad <br/> Hence, the number of revoluations <a href="https://interviewquestions.tuteehub.com/tag/completed-409685" style="font-weight:bold;" target="_blank" title="Click to know more about COMPLETED">COMPLETED</a> <br/> `n=(theta)/(2pi)=(20pi)/(2pi)=10`</body></html>