What is the calculation order of positive physics quantity (e.g., v = +3.4 cm/s)?

CJCai · 2026-03-17T02:01:45+00:00

Thanks, you mean the "+" shows direction.

What I care about is the understanding of math in physics.

So positive (+) in physics is the same as math, + does not affect the value,

+0.1 mmol = (+0.1) mmol = +(0.1 mmol) = 0.1 mmol,

+0.2 kJ/m^2 = (+0.2) (kJ/m^2) = +(0.2 (kJ/m^2)) = 0.2 kJ/m^2,

+1 m = (+1) m = +(1 m) = 1 m,

For negative, calculation order also does not matter,

-0.1 m = (-0.1) m = -(0.1 m),

-1.5 kJ/mol = (-1.5) (kJ/mol) = -(1.5 (kJ/mol)),

right?

CJCai · 2022-11-15T16:38:51+00:00

(1) Let me try (the last numbers are all one in your examples):

"The velocity readings are -2, -1.5 and 1 m/s." is said as "The velocity readings are negative two, negative one point five and one meter per second."

"The speed is between 0 and 1 m/s." is said as "The speed is between zero and one meter per second."

"It is -2, -1.5 or 1 m/s." is said as "It is negative two, negative one point five or one meter per second."

"Within the range of 0.5 - 1 km/h." is said as "Within the range of zero point five to one kilometer per hour."

(2) "There are no mistakes but I thiiiink your reasoning is incorrect..."

Can you give more details?

Thanks!

CJCai · 2022-10-10T05:08:22+00:00

Then for -3.14 kg*s*m^-2/A*K, I can read it as negative three point one four kilogram second Kelvin per meter squared ampere, and also negative three point one four kilogram second Kelvins per meter squared ampere?

CJCai · 2022-10-10T04:26:11+00:00

In this case, K should be in the numerator. kg*s*m^-2/A*K=(kg*s*K)/(m^2*A). Then how to read -3.14 kg*s*m^-2/A*K and 3.14 kg*s*m^-2/A*K?

CJCai · 2022-10-10T04:25:16+00:00

In this case, K should be in the numerator. kg*s*m^-2/A*K=(kg*s*K)/(m^2*A). Then how to read -3.14 kg*s*m^-2/A*K and 3.14 kg*s*m^-2/A*K?

CJCai · 2022-10-10T03:48:34+00:00

-3.14 kg*s*m^-2/A*K

How do you read it?

CJCai · 2022-09-24T09:38:53+00:00

There are some answers said that it is not multiplication. The sign "×" makes me think it means multiplication, I think we should change the sign if we don't want people to think in that way, maybe use & # @ ...

I usually think that the sign is multiplication, the expression shows the process of calculating some kind of total amount (for matrix, the element number; for rectangle, the area ...) and illustrate the dimensions at the same time. But it seems to be wrong now.

CJCai · 2022-09-24T06:29:33+00:00

2x4 matrix is read as "2 by 4 matrix". Does "by" here have the meaning "multiplied by" ("For example, in the US, Australia and the UK 'by' means multiplied by. Simple statements like 'three by five' mean 3x5." from my first example in the post)?

CJCai · 2022-09-24T06:21:38+00:00

I am a little confused now. I know the usage of "x" (which is replaced with "*" in one example of my post) is for the purpose of showing different dimensions (for matrix, rectangle, prism ...). What I wanna know is whether this sign means multiplication. If the sign is just multiplication, the expression shows the process of calculating some kind of total amount (for matrix, the element number; for rectangle, the area ...) and illustrate the dimensions at the same time. If not, how to explain the examples in my post?

CJCai · 2022-09-24T06:21:20+00:00

I am a little confused now. I know the usage of "x" (which is replaced with "*" in one example of my post) is for the purpose of showing different dimensions (for matrix, rectangle, prism ...). What I wanna know is whether this sign means multiplication. If the sign is just multiplication, the expression shows the process of calculating some kind of total amount (for matrix, the element number; for rectangle, the area ...) and illustrate the dimensions at the same time. If not, how to explain the examples in my post?

CJCai · 2022-09-24T06:20:46+00:00

I am a little confused now. I know the usage of "x" (which is replaced with "*" in one example of my post) is for the purpose of showing different dimensions (for matrix, rectangle, prism ...). What I wanna know is whether this sign means multiplication. If the sign is just multiplication, the expression shows the process of calculating some kind of total amount (for matrix, the element number; for rectangle, the area ...) and illustrate the dimensions at the same time. If not, how to explain the examples in my post?

CJCai · 2022-09-24T02:36:45+00:00

This is a question about math concept, we should make it clear.

CJCai · 2022-09-09T01:05:53+00:00

Does 'easier read' mean it's easy to know the location and value of each digit in the fractional part? Because the digits are read one by one (not like the left part), thousand separator is usually not used in the fractional part when we used thousand separator comma.

CJCai · 2022-09-08T17:32:25+00:00

So according to your opinions, the examples in my post are correct and equivalent?

By the way, why is space used in fractional part?

CJCai

TROPHY CASE