Question

# 1. A dentist using a dental drill brings it from rest to maximum operating speed of...

1. A dentist using a dental drill brings it from rest to maximum operating speed of 364,000 rpm in 3.2 s. Assume that the drill accelerates at a constant rate during this time.

(a) What is the angular acceleration of the drill in rev/s2?

rev/s2

(b) Find the number of revolutions the drill bit makes during the 3.2 s time interval.

rev

2. In a laundromat, during the spin-dry cycle of a washer, the rotating tub goes from rest to its maximum angular speed of 2.2 rev/s in 7.3 s. You lift the lid of the washer and notice that the tub decelerates and comes to a stop in 19.5 s. Assuming that the tub rotates with constant angular acceleration while it is starting and stopping, determine the total number of revolutions undergone by the tub during this entire time interval.

3. At its peak, a tornado is 63.0 m in diameter and carries 275-km/h winds. What is its angular velocity in revolutions per second?

4. a. Calculate the linear acceleration of a car, the 0.230-m radius tires of which have an angular acceleration of 15.0 rad/s2. Assume no slippage and give your answer in m/s2.

m/s2

(b) How many revolutions do the tires make in 2.50 s if they start from rest?

rev

(c) What is their final angular velocity in rad/s?

(d) What is the final velocity of the car in m/s?

m/s

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