Q1. A potter's wheel having a radius 0.47 m and a moment of inertia 10.9 kg•m2 is rotating freely at 46 rev/min. The potter can stop the wheel in 7.0 s by pressing a wet rag against the rim and exerting a radically inward force of 68 N. Find out the effectual coefficient of kinetic friction between the wheel and the wet rag.
Q2. A projectile is fired horizontally from a gun that is 37.0 m above flat ground; emerging from the gun with a speed of 390 m/s. (a) how long does projectile remain in the air? (b) At what horizontal distance from firing point does it strike the ground? (c) What is magnitude of the vertical component of its velocity as it strikes the ground?