The slope of a position/time graph is the speed of the motion.
(The slope doesn't 'determine' the speed; it only displays it.)
The slope of a speed/time graph is the acceleration of the motion.
Answer:
c) 8.3 x 10^24 molecules
Explanation:
First of all, we convert the volume of the glass of water from mL to
:

The relationship between mass and volume is:

where
is the density of water
M is the total mass of the glass of water
is the volume of the water in the glass
Solving for M,

Now we know that the mass of a single molecule of water is

The total mass of the water in the glass can be written as

where
N is the number of molecules in the glass of water
Solving for N, we find:

It has to move through a distance over time.
What do you mean? Is there a picture ?