The tub of a washer goes into its spin-dry cycle, starting from rest and reaching an angular speed of 2.0 rev/s in 11.0 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 9.0 s. through how many revolutions does the tub turn during this 20 s interval? assume constant angular acceleration while it is starting and stopping.

Total angular displacement will be  19.998 radian  

Explanation:

It is given that the washer starts from the rest and reach reach the speed of 2 rev/sec in 11 sec

So initial angular velocity

And final angular velocity

Time t = 11 sec

So angular acceleration

So angular displacement in this 11 sec

Now the washer slows down and stops in 9 sec

So final angular velocity = 0 rad/sec

So angular acceleration

So angular displacement

So total displacement in 20 sec =

the duration of a photographic flash is related to an rc time constant, which is 0.100 μs for a certain camera.

the components of a vector are the parts of the vectors that are to each other.

b perpendicular