<span>The scientist thought that the
atom was the smallest particle in the universe is John Dalton. The answer is
letter B. He established the atomic theory which consists of five; elements are
made of extremely small particles called atoms, atoms of different element have
different sizes, mass and physic – chemical properties, atoms cannot be divided
further, destroyed or created, atoms can combine to form compounds and in
chemical reaction, atoms can be combined, separated or rearranged. J.J.
Thompson discovered the electrons in the atom. Ernest Rutherford discovered the
half – life of an atom and Neils Bohr explain the quantum mechanics.</span>
<span>A compound machine is a combination of two or more "Machines"
Hope this helps!</span><span />
Good question. if it's a physical change what you would see is a change in the physical object/appearance like let's say I Tear a piece of paper, that would be a Physical change. I believe your answer would be a chemical change.
The boys body will continue to move in a forward motion, the stairs an an will make the skateboard come to a complete stop because the force of the stairs is much greater, this makes in an unbalanced force. This is and example of inertia of motion.
Answer:
Object 2 has the larger drag coefficient
Explanation:
The drag force, D, is given by the equation:

Object 1 has twice the diameter of object 2.
If 

Area of object 2, 
Area of object 1:

Since all other parameters are still the same except the drag coefficient:
For object 1:

For object 2:

Since the drag force for the two objects are the same:

Obviously from the equation above, c₂ is larger than c₁, this means that object 2 has the larger drag coefficient