The tub of a washer goes into its spin-dry cycle, starting from rest and reaching an angular speed of 7.0 rev/s in 7.0 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 13.0 s. through how many revolutions does the tub turn during this 20 s interval? assume constant angular acceleration while it is starting and stopping.