## The tub of a washer goes into its spin-dry cycle, starting from rest and reaching an angular speed of 3.0 rev/s in 13.0 s. At this point, th

Question

The tub of a washer goes into its spin-dry cycle, starting from rest and reaching an angular speed of 3.0 rev/s in 13.0 s. At this point, the person doing the laundry opens the lid, and a safety switch turns off the washer. The tub slows to rest in 12.0 s. Through how many revolutions does the tub turn during this 25 s interval

in progress 0
2 days 2021-07-20T10:59:29+00:00 1 Answers 4 views 0

The tub turns 37.520 revolutions during the 25-second interval.

Explanation:

The total number of revolutions done by the tub of the washer ( ), in revolutions, is the sum of the number of revolutions done in the acceleration ( ), in revolutions, and deceleration stages ( ), in revolutions: (1)

Then, we expand the previous expression by kinematic equations for uniform accelerated motion: (1b)

Where: – Angular accelerations for acceleration and deceleration stages, in revolutions per square second. – Acceleration and deceleration times, in seconds.

And each acceleration is determined by the following formulas:

Acceleration (2)

Deceleration (3)

Where is the maximum angular velocity of the tub of the washer, in revolutions per second.

If we know that , and , then the quantity of revolutions done by the tub is:       The tub turns 37.520 revolutions during the 25-second interval.