Q. A laser beam is incident on a 45°-45°-90° prism perpendicular to one of its faces. The transmitted beam that exits the hypotenuse of the prism makes an angle of 15° with the direction of the incident beam. Find the index of refraction of the prism. (Use the following as necessary: θ1 = 15°, θ2 = 45°)

Q. A block of wood of mass 2 kg is suspended by long, light strings and is at rest. A bullet of mass 40 g, strikes and remains in the block, causing it to swing. The maximum height of the block above its rest position is 51 cm. Find:

a) the kinetic energy of the bullet plus block immediately after impact;
b) the velocity of the bullet at impact
c) the kinetic energy of the bullet at impact.
Why are the answers to a) and c) not equal?