Why has the model of the atom changed over time?
a.
the model of the atom evolved as scientists have made new discoveries.
b.
the model of the atom is only correct if it is identical to the size of an atom.
c.
the current model of the atom is simple with exaggerated size.
d.
atoms are too complex and cannot be explained using a model.

Acatapult is tested by roman legionnaires. they tabulate the results in a papyrus and 2000 years later the archaeological team reads (distances translated into modern units): range = 0.4 km; angle of launch = π/5 rad; landing height = launch height. what is the initial velocity of launch of the boulders if air resistance is negligible?

Anybody wanna ? (picture included? )

Mechanical energy is when the amount of kinetic and potential energies added together remains the same. conserved created lost