Lavoisier made a list of thirty-three elements. his list of elements challenged the age-old idea that
a) elements are made of atoms.
b) there are only four elements.
c) elements cannot be identified.
d) elements do not exist in the free state.

The air that we breath is made mostly of which gaseous molecule

You throw a small rock straight up from the edge of a highway bridge that crosses a river. the rock passes you on its way down, 7.00 s after it was thrown. what is the speed of the rock just before it reaches the water 28.0 m below the point where the rock left your hand? ignore air resistance.

The friction of the water on a boat produces an acceleration of -10. m/s2. if the boat is traveling at 30. m/s and the motor is shut off, how long it take the boat to slow down to 5.0 m/s?