Adisk with moment of inertia i relative to a vertical axis through its center is dropped onto another disk with moment of inertia equal to 2i which is rotating with angular velocity . find the final angular velocity in terms of .

Consider an ordinary, helium-filled party balloon with a volume of 2.2 ft3. the lifting force on the balloon due to the outside air is the net resultant of the pressure distribution exerted on the exterior surface of the balloon. using this fact, we can derive archimedes’ principle, namely that the upward force on the balloon is equal to the weight of the air displaced by the balloon. assuming that the balloon is at sea level, where the air density is 0.002377 slug/ft3, calculate the maximum weight that can be lifted by the balloon. note: the molecular weight of air is 28.8 and that of helium is 4.

If steel is more dense that lake water, why can a boat float

What are similarities and differences of reflection, refraction, diffraction and absorption?