Aswimming pool measures 45.0 meters by 30.0 meters. how many grams of water are needed to fill the pool, whose average depth is 7.2 feet? assume the density of water to be 1.0 g/ml. report answer to 3 significant figures. do not enter “grams” as part of your answer. use “e” for scientific notation.

mass of water = 2962656000 = 2.963 E9 grams

Explanation:
1 ft = 0.3048 m
Therefore:
7.2 ft = 2.19456 m

First, we will get the volume of the swimming pool as follows:
The swimming pool has a rectangular shape, this means that:
volume of pool = length * width * depth
volume of pool = 45 * 30 * 2.19456 = 2962.656 m^3

Now, we will get the mass of needed water as follows:
density = mass / volume
we have:
density = 1 g/ml
volume = 2962.656 m^3 = 2962656000 ml
Substitute to get the mass of water as follows:
mass of water = density * volume = 1 * 2962656000
mass of water = 2962656000 = 2.963 * 10^9 grams

Hope this helps :)

They can measure  the amount of energy gained or lost