PHY120 study review
Physics

Tutor: None Selected  Time limit: 1 Day 
The tub within a washer goes into its spin cycle, starting from rest and reaching an angular speed of 15π rad/s in 6.6 s. At this point, the lid is opened, and a safety switch turns off the washer. The tub slows to rest in 16.6 s. Through how many revolutions does the tub turn? Assume constant angular acceleration while the machine is starting and stopping. Answer in units of rev.
Thank you for the opportunity to help you with your question! the solution is as such:
Thank you for the opportunity to help you with your question! the solution is as such:
when the lid is opened, u= 16 π rad/s
final velocity v= 0 π rad/s
we know, v= u + at (here a denotes alpha i.e. acceleration for circular motion)
where t= 16.6s
so a = 0.95 π rad/s ^ 2
now v^2 = u^ 2 + 2aS
so, S= 145.03 rads.
1 revolution require 2 π rads
so, this is equivalent to 145.03/2 so it will take almost 72.5 revolutions in stopping.
Please let me know if you need any clarification. I'm always happy to answer your questions.awaiting a positive feedback. thank you.
I tried to put the value 72.5 in my homework web page and it was the wrong answer. Is there another way to solve this problem?
try 72 0 or 73
we know, v= u + at (here a denotes alpha i.e. acceleration for circular motion)
where t= 16.6s
so a = 0.90π rad/s ^ 2
now v^2 = u^ 2 + 2aS
so, S= 153.0 rads.
1 revolution require 2 π rads
so, this is equivalent to 153.0 /2 so it will take almost 76.5 revolutions in stopping.
Please let me know if you need any clarification. I'm always happy to answer your questions.awaiting a positive feedback. thank you.
u can try with 76 or 77. for any doubts.i am happy to guide you further
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