Question

A rock is 7 feet below the surface of a river. If its position can be recorded as −7 feet, what would the position of 0 represent?

On the surface of the river

At the bottom of the river

7 feet above the surface of the river

7 feet below the surface of the river

Answer 1

Okay so we know it is BELOW the surface. Meaning the SURFACE is probably the equal line. What I mean by equal is the middle line, line of equilibrium, etc.

So if it is the "normal" point or the surface point what would that be?

Answer 2

0 Right!

Answer 3

I got this..okay so which answers can we eliminate?

Answer 4

So, what do you think 0 is now?

@Tal_Tal

Answer 5

Well, lets eliminate again!

Do you think it is A?

@Tal_Tal

Answer 6

Its not A

Answer 7

First off, where is 0? because we know that the rock is 7 feet below it.

Answer 8

Why isn't it A?

@Tal_Tal

Answer 9

Because 7 is below it

Answer 10

but we don't know where 0 is yet, so A is still an option.

Answer 11

Right but it is asking what is 0...

Right?

@Tal_Tal

Answer 12

What about B?

Answer 13

Yes, A is still an option.

Answer 14

Now B?

Answer 15

Why or why not is B the answer?

Answer 16

First, figure out which answers do not make any sense? For example, The rock is or is not at the bottom of the river?

Answer 17

Its not because on the number line 0 is in the middle?

Answer 18

correct!

Answer 19

but also, what about C and D? is the rock above or below the river?

Answer 20

Below?

Answer 21

yes, so we can eliminate those two answer. Now, what is your answer?

Answer 22

D?

Answer 23

Nope, because remember, -7 is lower than 0

Answer 24

A?

Answer 25

Yep!

Answer 26

Do you still need help with this @Tal_Tal ? If you don't please close the question, if you do, I can help you.

Answer 27

make sure to medal and fan!

Answer 28

Good job!

@Tal_Tal

Answer 29

@Tal_Tal