Math Equations. - Page 2

cold1 · 07-08-2014, 16:11

I second Ohms law and Pythagorens.

For electronics the watts equation cant be beat. Google "watts equation wheel" and see the images.

On youtube there is a channel called Numberphile. Some of it is way advanced but there is some that can be of interest to 7-8 graders.

As a student, i never "got" math. When I entered the service and learned electrionics and all the equations that went with it, suddenly everything fell into place and math made sense.

Longstreet · 07-08-2014, 16:54

Quote:

I'm not following how he said it couldn't be done?
That gag was indeed genuine. No wires or mirrors were used.
What you see on film is how it actually happened.

I believe his calculations were based on that Bond had completely stopped the car and then had about five seconds to accelerate it to do the stunt. In reality the car would have needed more time to accelerate to a faster speed that would have permitted him to do the maneuver.

I am sorry that I cannot elaborate on it more as I was in his physics class over 20 years ago and as mentioned I was not a good student.

Phunny how some things just stay in your head . . .

cbtengr · 07-08-2014, 17:32

Quote:

Originally Posted by CSB

The amount of TNT needed to destroy a timber beam (applied externally) is:

P= D ^2 / 40

(That's P equals D squared, divided by 40)

Where:
P = Amount of TNT in pounds
D = Dimension of beam in inches

If the engineer can auger a big enough hole to the center of the timber,
the amount of TNT for an internal charge drops to:

P = D ^2 / 250

Notice how the constant divisor increased in size, decreasing the amount of TNT needed.

====================

For a bulk steel cutting charge, simply estimate the number of square inches
in the steel beam, then use:

P = 3/8 A

Where "P" = Pounds of TNT and "A" equals the Area of the structure in square inches.

For steel bars, cables and chains, simply use P =A. Sounds simple, but a 2 inch in diameter steel rod has a cross section of?

... Anyone? anyone?

Pi x R ^2 (The area of a circle) produces the area.

for a one inch radius (2 inch diameter) that's 1 x 1 x 3.14 = 3.14 inches cross section, yielding 3 1/4 lbs of TNT.

All this time I thought it was "P" for Plenty

.

Sdiver · 07-08-2014, 17:50

Quote:

Originally Posted by Longstreet

Jayson here and I believe his calculations were based on that Bond had completely stopped the car and then had about five seconds to accelerate it to do the stunt. In reality the car would have needed more time to accelerate to a faster speed that would have permitted him to do the maneuver.

I am sorry that I cannot elaborate on it more as I was in his physics class over 20 years ago and as mentioned I was not a good student.

Phunny how some things just stay in your head . . .

jaYson

Ahhhh ... okay. I can see what he was getting at.
I'm sure that when they did the gag, Milligan had plenty of room to get up to the speed he needed.
I've been looking for any "behind the scenes" videos of that gag, NOT ones like Pat posted.

Grabbing a video from Top Gear with "Capt. Slow" narrating. ... I mean com'on really ?????
Jeeeeezzzzzzzzzzzzzzzz

ETA: So far this is the only video I've been able to find. As you can see it's full speed, minus that annoying "slide whistle" sound effect.

http://www.youtube.com/watch?v=trJocyjCBzo

PSM · 07-08-2014, 17:54

Quote:

Originally Posted by CSB

The amount of TNT needed to destroy a timber beam (applied externally) is:

P= D ^2 / 40

(That's P equals D squared, divided by 40)

Where:
P = Amount of TNT in pounds
D = Dimension of beam in inches

If the engineer can auger a big enough hole to the center of the timber,
the amount of TNT for an internal charge drops to:

P = D ^2 / 250

Notice how the constant divisor increased in size, decreasing the amount of TNT needed.

====================

For a bulk steel cutting charge, simply estimate the number of square inches
in the steel beam, then use:

P = 3/8 A

Where "P" = Pounds of TNT and "A" equals the Area of the structure in square inches.

For steel bars, cables and chains, simply use P =A. Sounds simple, but a 2 inch in diameter steel rod has a cross section of?

... Anyone? anyone?

Pi x R ^2 (The area of a circle) produces the area.

for a one inch radius (2 inch diameter) that's 1 x 1 x 3.14 = 3.14 inches cross section, yielding 3 1/4 lbs of TNT.

These should go over well in today's 7th Grade classes.

LR1947 needs to post some ballistics equations.

Pat

Longstreet · 07-08-2014, 18:32

Although this is not an equation with variables, I have used it to introduce the concept of how something can be proven using numbers -all in fun of course.

Given: Barney is a CUTE PURPLE DINOSAUR
Prove: Barney is Satanic

The Romans had no letter 'U' and used 'V' instead for printing, meaning the Roman representation for Barney would be:

CVTE PVRPLE DINOSAVR
Extracting the Roman numerals, we have:

C V V L D I V
Decimal Equivalents are:

100 5 5 50 500 1 5
Adding those numbers produces: 666

666 is the number of the beast.

Therefore, Barney is Satan.

Someone really had time on her/his hands.

Longstreet · 07-08-2014, 18:36

Quote:

Ahhhh ... okay. I can see what he was getting at.
I'm sure that when they did the gag, Milligan had plenty of room to get up to the speed he needed.
I've been looking for any "behind the scenes" videos of that gag, NOT ones like Pat posted.

They used a similar strategy in The Empire Strikes Back when Luke is thrown out of the window on Bespin. For the scene Lucas used a gymnast to do several flips before landing threw the window.

Quote:

These should go over well in today's 7th Grade classes. LR1947 needs to post some ballistics equations.

I know and I am hoping to get more like it. We will definitely have some good discussions with this one.

PSM · 07-08-2014, 18:59

Quote:

Originally Posted by Sdiver

Ahhhh ... okay. I can see what he was getting at.
I'm sure that when they did the gag, Milligan had plenty of room to get up to the speed he needed.
I've been looking for any "behind the scenes" videos of that gag, NOT ones like Pat posted.

Grabbing a video from Top Gear with "Capt. Slow" narrating. ... I mean com'on really ?????
Jeeeeezzzzzzzzzzzzzzzz

ETA: So far this is the only video I've been able to find. As you can see it's full speed, minus that annoying "slide whistle" sound effect.

http://www.youtube.com/watch?v=trJocyjCBzo

OK, that's more convincing, but they clearly beefed up the suspension so that it didn't end up like TG's with the radical shift of weight on landing on a single rear wheel.

BTW, CPT Slow did get to fly in a U-2. Assign me any nickname you want if you can get me a ride in one.

Pat

PTF Guy · 07-08-2014, 19:32

60 Miles per Hour = 88 Feet Per Second

Light (or radar/radio waves, X-rays or heat) travels 1 foot in 1 nanosecond.

UWOA (RIP) · 07-08-2014, 20:40

Attachment 28426

Quote:

Originally Posted by Longstreet

Jayson here and does anyone know of any math equations - particularly used in the military - that people use to help make decisions? I teach Grade 7 math and found that my students really struggled with equations and variables partially because they did not fully understand their significance in the real world. I used the classic E=MC2 as well as the equation the police use to determine the speed of a car using its skid marks, but only a few of my students got it. I would like to put together a list over the summer so that they will be better able to see the power of equations and hopefully see their importance. Please note that if you can provide one, can you please identify the variables and no you do not need to explain it with an actual example. I just need to know the equation and what it does. Thanks.

jaYson

I taught decision matrices at the US Army Command and General Staff College and later ported the information into the law enforcement arena (as well as designing and coding a program that does all the work for the user).

Here is the power point that supports that effort:

JJ_BPK · 07-09-2014, 05:14

Quote:

Originally Posted by PSM

These should go over well in today's 7th Grade classes.

LR1947 needs to post some ballistics equations.

Pat

That's what I'm thinking. There is a bunch of math use when trying to figure out trajectory, drift, gravity, moon phases, the earth's rotation??

1stindoor · 07-09-2014, 06:20

I also remember one about working for a month for only a penny a day, but it is doubled every day for the month. At the end of the month I think the pay was something over 5 mil. (dollars...not pennies)

Sdiver · 07-09-2014, 09:19

Quote:

Originally Posted by 1stindoor

I also remember one about working for a month for only a penny a day, but it is doubled every day for the month. At the end of the month I think the pay was something over 5 mil. (dollars...not pennies)

That is an example I use constantly.

Here's what it looks like .... http://mathforum.org/dr.math/faq/faq...g.pennies.html

Golf1echo · 07-09-2014, 11:44

CSB touched on it from the opposite end : The math of structure can be very useful in knowing and understanding your environment. Understanding simple span and load problems can be helpful in any building projects the students may become involved in but it can also contribute to their safety. Deck collapse and failure is one example, just knowing the basics and what to look for could be a life saver one day. Children can grasp more than one might think if basic information is well presented, for some, structure is intuitive. Here are a few links that might get you started : http://www.childrensengineering.com/linksstructures.htm
http://www.technologystudent.com/forcmom/forcedex.htm