The most distant object a human can see without the aid of an optical device (such as a telescope) is the Andromeda Galaxy approximately 2.5 million light years away. If we consider a photon traveling from that galaxy to you here on Earth; (a) How long does it take the photon to travel to us in our reference frame?
(b) How much time is experienced by the photon during this journey?
(c) Comment on your answers.

An object is 10. cm from the mirror, its height is 3.0 cm, and the focal length is 2.0 cm. what is the image height? (indicate the object orientation by including the + or - sign with the answer.) hi = cm +1.33 -1.33 +0.75 -0.75

Which of the following is an example of motion in two dimensions?

Aboat radioed a distress call to a coast guard station. at the time of the call, a vector a from the station to the boat had a magnitude of 45.0 km and was directed 15.0° east of north. a vector from the station to the point where the boat was later found is = 30.0 km, 15.0° north of east. what are the components of the vector from the point where the distress call was made to point where the boat was found? in other words, what are the components of vector c = b - a?