The observation deck of tall skyscraper 311 m above the street. determine the time required for a penny to free fall from the deck to the street below. (make x negative since the penny is falling)

8.0 s

Explanation:

The penny is in free fall, so its motion is a uniform accelerated motion with constant acceleration; therefore we can use the following suvat equation:

where

s is the displacement

u = 0 is the initial velocity of the penny

t is the time

is the acceleration of gravity

The displacement is

s = -311 m

So we can re-arrange the equation to solve for t, the time of flight:

i think the answer is a, hope this is right, that would be my best guess.

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.