How was Edwin Hubble able to use his discovery of Cepheids in Andromeda to prove that the "spiral nebulae" were actually galaxies external to the Milky Way?

A physics student swings a pail of water in a vertical circle 1.0 m in radius at a constant speed. If the water is NOT to spill on him/her: (A) calculate the minimum speed of the pail of water (B) calculate the maximum time per revolution (period)

What is the potential energy of a 25 kg bicycle resting at the top of a hill 3 m high? (Formula: PE = mgh) 0 75 J 735 J O 245 J 0 37.8 J

Explain what kind of heat transfer occurs when you burn yourself on a hot car seat in the summer.

circular saw blade of diameter 0.190 m starts from rest. In a time interval of 5.80 s it accelerates with constant angular acceleration to an angular velocity of 145 rad/s. Part A Find the angular acceleration.

If a wave has a speed of 200 m/s and a wavelength of 20 meters, what is the frequency?

The correctly balanced equation for H2O2 → H2O + O2 is

How would an unbalanced chemical equation convey misleading information about what took place during a chemical reaction?

A car rounds a 75-m radius curve at a constant speed of 18 m/s. a ball is suspended by a string from the ceiling the car and moves with the car. the angle between the string and the vertical is:

Emission of light from an atom occurs when an electron

Which is an example of transfroming potential energy to kinetic