150 yd3 of water - what is the mass in pounds of water?

  • Thread starter Thread starter master c
  • Start date Start date
  • Tags Tags
    Mass Water
Click For Summary
To calculate the mass of 150 cubic yards of water, first, understand that 1 cubic yard equals 27 cubic feet. Therefore, 150 cubic yards equals 4,050 cubic feet. The weight of water is approximately 62.4 pounds per cubic foot, so multiplying 4,050 cubic feet by 62.4 pounds gives a total mass of about 252,120 pounds. The initial assumption of calculating volume as 150 cubed was incorrect; instead, focus on the correct conversion and multiplication for accurate results. This approach clarifies the relationship between volume and mass in this context.
master c
Messages
1
Reaction score
0
Hi all,

I do hope I have chosen the right forum thread to ask this question. I don't want to waste anyones time. I am trying to help guide my girlfriend with some physics questions with not much luck. One question that we are struggling with is:

A typical backyard swimming pool holds 150yd3 of water.

What is the mass in pounds of water?

So I believe you would do 150 cubed which is 150 x 150 x 150 = 3375000 yards of water in the pool - am i correct? However from there I am lost in regards to working out what the mass in pounds of water is?

Many thanks to anyone in advance which can guide us through breaking down and answering such a question.
 
Physics news on Phys.org
You have to multiply the volume with the density (\rho)

Volume x \rho = mass
 
master c said:
A typical backyard swimming pool holds 150yd3 of water.

So I believe you would do 150 cubed which is 150 x 150 x 150 = 3375000 yards of water in the pool
- am i correct?
No.

Math learning is first about intuiting the answer. Intuitively, have you ever seen a pool that is 150 yards long and wide, and 150 yards deep?

This should tell you there's something wrong with your first assumption.

What is the volume of this pool?
 
A typical 3-axle dump truck holds nearly 15 cubic yards of material, so how many of those would you need to be equivalent to the volume of your swimming pool? Can you visualize that?

It's pretty easy to find out what the weight of a cubic foot of water weighs, so how many cubic feet in a cubic yard, and what can you get for the weight of a cubic yard of water?

Take a stab at the calculation, so we can see if you understand the problem, and if not, why not.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

Similar threads

  • · Replies 10 ·
Replies
10
Views
3K
Replies
12
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 12 ·
Replies
12
Views
8K
Replies
2
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 38 ·
2
Replies
38
Views
5K
  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K