(a) why are sound waves called mechanical waves ? list two practical applications of reflection of these waves. (b) a stone is dropped from the top of a tower 125 m high into a pond of water at the base of the tower. when is the splash heard at the top ? (g = 10 m/s2 and speed of sound = 340 m/s)

Why do astronauts in the space shuttle weigh less?

Describe the three ray tracing steps used to identify an image for the given situation.

12. ritu obtained a distinct image of a distant tree on the screen with the of a concave mirror.to find the focal length of the mirror she has to measure the distance between: (a) mirror and the tree. (b) screen and the tree.(c) mirror and the screen. (d) mirror and tree as well as between screen and the tree.