Energy that tracked in waves though matter is?

If angle "a" is 25°, angle "b" is: a) equal to angle c b) less than angle c c) greater than angle c

What is the weight of a feather (mass = 0.0001 kg) that floats through earth's and the moon's atmospheres?

Aball thrown by ginger is moving upward through the air. diagram a shows a box with a downward arrow. diagram b shows a box with an upward arrow. diagram c shows a box with a downward and upward arrow equal in size. diagram d shows a box with a downward and upward arrow with the downward arrow larger in size. which force diagram represents the forces on the ball? you may neglect the effects of air resistance.