Q. A plate of glass 8.50 long is placed in contact with a second plate and is held at a small angle with it by a metal strip 7.80×10-2 thick placed under one end. The space between the plates is filled with air. The glass is illuminated from above with light having a wavelength in air of 656 . How many interference fringes are observed per centimeter in the reflected light?
Q. A basketball, of mass m = 0.45 kg is dropped, from rest, from a stationary hellicopter at a high altitude. Use g = 9.81 N/kg.
If air resistance is negligible, using energy considerations alone, how fast should the ball be going after it falls 200 meters?