Explanation :
Antoine-Laurent Lavoisier reported four "element" classifications but included some substances that were combinations of elements rather than true elements in his listing.
He is also known as " father of modern chemistry". He gives the modern system of naming chemical substances. He also gives a theory for chemical reactivity of the oxygen.
the answer of this question is helium
Answer:
Explanation:
Assuming no friction between the roller coaster car and the hill, and neglecting air resistance, the kinetic energy the roller coaster car would have at the bottom of the hill would be equal to its gravitational potential energy at the top of the hill, by conservation of energy.
Answer:
Explanation:
We must use conservation of linear momentum before and after the collision, 
Before the collision we have:
where these are the masses are initial velocities of both players.
After the collision we have:
since they clong together, acting as one body.
This means we have:
Or:
Which for our values is:
