Even though the hubble law for galactic motions indicates that the spectra of all galaxies should show redshift as a consequence of the general expansion of the universe, the andromeda galaxy m31 appears to show a blueshift in its spectrum. why is this?

An experiment is designed to test the relationship between the initial height of a basketball before it is dropped to the height of its rebound bounce. the height of the rebound bounce is measured using a scale positioned behind the ball. in the above experiment, which condition would not be controlled? a). the starting height of the ballb). the surface the ball bounces on c). the type of ball d). the method to measure the rebound height of the ball

Waves that cause the most damage during an earthquake are a. surface waves c. s waves b. p waves d. ocean waves

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.