Joey's little brother makes a ramp to push hos toy dump truck up to his sandbox. if he uses 5N of force to push the 12N truck up the ramp, what is the mechanical advantage of his ramp? A. 6.0
B.0.42
C. 2.4
D. 23.5​

Light from the sun reaches the earth in 8.3 minutes. the velocity is 3.00 x 10^8 m/s. how far is earth from the sun? i know how to get to d = (3 x 10^8 m/s)(498 sec). i just don't know how to get from there to the answer being 1.5 x 10^11 m.

Critical mass is the of material required to produce a chain reaction. a.) minimum amount b.) atomic mass c.) precise amount d.) maximum amount

The necleus of an atom is made up of what subatomic particles?