Question 25 2.5 pts
Which of the following statements describes a difference
between a chemical change and a physical change in a
substance?
Tim
Attei
231
o The result of a chemical change is a different
composition; in a physical change, the composition
remains the same.
o A physical change occurs only in elements: a
chemical change occurs only in compounds.
O A chemical change occurs only in elements; a
physical change occurs only in compounds.
The result of a physical change is a different

o The result of a chemical change is a different  composition; in a physical change, the composition  remains the same.

Explanation:

In a chemical change, new kinds of matter are produced although the atoms are the same.

For physical changes, no new kinds of matter formed. Only the state of substances changes.

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.

that would be because of both gravity and friction. so     c