Why was copernicus’s heliocentric model not believed until galileo and kepler provided more evidence?
a. the model had the moon orbiting earth.
b. the model was against religious teachings.
c. the model could not explain retrograde motion.
d. the model did not include all eight planets in the solar system.

Red light strikes a metal surface and electrons are ejected. if violet light is now used with a 10% greater intensity, what will happen to the ejection rate (number of ejected electrons per second) and the maximum energy of the electrons? a) greater ejection rate; same maximum energyb) same ejection rate; greater maximum energyc) greater ejection rate; greater maximum energyd) same ejection rate; same maximum energye) none of the above answers are correct

Awave has a wavelength of 7 mm and a frequency of 19 hertz. what is its speed?

What energy transformations occur each time the skateboarder rolls up the ramp?