More Maths. No Sweat!!!

September 11, 2009

Mathspigs there are two things that stop kids doing maths. Fear & boredom. But we are going to show NO FEAR. You may find some of these equations a bit scary. I do too. But I can make some sense of some of this stuff. Here goes.

The article No Sweat. Well, not as Much as You think (New Scientist 18/7/09 #mce_temp_url#  ) highlighted research by the US army into finding an equation for how much men and women sweat. They need this information so they can calculate how much water they need to carry. Makes sense.

How do they calculate how much you sweat???

Basically, they use NUDE body mass work out how much weight you lose after exercise. Allowances are made for mass (or weight) by breathing in oxygen and breathing out water & carbon dioxide.

They can also calculate how much heat is lost when you are nude if  m  ( or m with a little dot) is your sweat rate in grams per hour.

Then things go a little crazy. Here’s one part of the equations for heat lost when dressed. I just want you too see how crazy some equations can be.  We’re not going to use it. But when you are doing studies like this you get used to such equations.

ARE WE SCARED, MATHSPIGS? No. We’re going IN to look at the results. We can make sense of them.

Thanks to Dean Van DEn Heuvel, Kyneton, Victoria for this fab math pig pic. We like happy mathspigs!!!!

When you read the table below keep in mind:

How much do you sweat????

With one more piece of data you can calculate how much you would sweat in Battle Dress Uniform or body Armor plus vest. Your surface area:

“Normal” BSA is generally taken to be 1.73 m² for an adult. ( More @ Wikipedia: #mce_temp_url#)

Average BSA values
Child 9 years 1.07
Child 10 years 1.14
Child 12-13 years 1.33
For men 1.9
For women 1.6

Which sport is more DANGEROUS to play? Cricket or baseball?

September 4, 2009

Mathspigs you are about to be hit on the head with some BALL PARK figures. There is so much maths involved in comparing cricket and baseball I hardly know where to begin. So I will just set you up with comparitive statistics for starters. Here they are:

You now have sufficient information to calculate the following:

Q1. If a cricket player  makes 4 runs (and runs between the wickets) and a baseball player hits a home run, who runs the furtherest?

Q2. What are the delivery ball speeds of an average pitcher and a mid paced bowler in m/sec?

Q3. How far would the delivery of an average pitcher and a  medium paced bowler travel in 10 seconds?

Q4. If Shoaib Akhar fielded a ball in cricket 20 m from the wicket when the batsman was still 8m from the wicket (A typical running speed for humans is 32 km/h) would he be able to run him out?

Q5. How long would it take a ball thrown by Joel Zumaya to reach the batsman if the pitchers mound was exactly in the middle of the baseball square?

Q6. Which sport is more dangerous? We will base our calculations on the speed (or velocity) and the weight (or mass) of the ball. We must use the same units in all calculations. For each sport plot x-axis: velocity of ball (v) against y-axis mass x velocity (mv) of the ball. mv is the momentum. In ballistics the change in momentum is called the IMPULSE (impact for us). If you are hit on the head with a ball it is the change in momentum of the ball that does the damage. A small ball at a high speed can do as much damage as a larger ball at a slower speed. We are not including spin, curve balls or air resistance to keep calculations straight forward … literally!!!