A boat is traveling at speed v0 on a lake when it turns off its engine. The boat is subject to a drag force that is proportional to the cube of the boat’s speed. In other words Fd = −bv3 Find the time it takes for the boat’s speed to decrease to half its initial value.

At 20∘c, the hole in an aluminum ring is 2.800 cm in diameter. you need to slip this ring over a steel shaft that has a room-temperature diameter of 2.804 cm . 1. to what common temperature should the ring and the shaft be heated so that the ring will just fit onto the shaft? coefficients of linear thermal expansion of steel and aluminum are 12×10−6 k−1 and23×10−6 k−1 respectively.