A wheel with radius r rotates freely about its axle with initial angular speed ωi. A point on the wheel's rim moves at linear speed v. Suddenly, the wheel accelerates so the point moves at linear speed 3v. The final angular speed is ωf.
How does the angular speed of the wheel change?

15. one purpose of the tread pattern on a tire is to a reduce tire wear. b. reduce traction c. allow water to flow away from the tire. d. look impressive.

Holes drilled several kilometers into earth’s crust provide direct evidence about earth’s interior in the form of

Arigid tank is divided into two equal parts by a partition. one part of the tank contains 3 kg of compressed liquid water at 400 kpa and 60°c while the other part is evacuated. the partition is now removed, and the water expands to fill the entire tank. determine the entropy change of water during this process, if the final pressure in the tank is 40 kpa. use steam tables.