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:

ANOTHER RUNNING DOG
Explanation:
In the given question it is to find a suitable reference point to describe the motion of dog. Here I could suggest that it is better to compare the dog with another running dog to create the relative speed difference to get a reliable motion variation.
Because the motion of dog is in the linear with respect to the another dog and to the acceleration produced by the dog in the required interval is easy to calculate with respect to another dog which is already in motion.
Hence, I suggest that Motion of dog can be analysed better by analyse the motion variation of dog with another dog running.
Answer:
Answer for the question is given in the attachment.
Explanation: