## Archive for May, 2011

### Who is Inertia?

Tuesday, May 31st, 2011

- Did you see the video above?
- It confused me!
- Confusion is good, isn’t it?
- Who is Inertia? I’ve never met her.

- The question was: Is it difficult to push the car because of its mass, its weight, or something else?
- If the car is at rest you have to accelerate it a bit to get it moving.
- Was it Newton who said F = ma?
- To move the car you have to exert a horisontal force greater than the force of resistance.
- The force of who?
- The force of resistance = constant times the weight of the car.
- So the force I need to move the car depends on the weight of the car?
- Or the mass, since without mass there is no weight.
- Are you suggesting that if the car has no mass I don’t need any force to move it?

### Quote

Tuesday, May 31st, 2011

Ocean: A body of water occupying about two-thirds of a world made for man – who has no gills. - Ambrose Bierce

### Art without a calculator

Monday, May 30th, 2011

- What is that?
- Oh, that is just a cube with cubes of the same size glued to its six sides.
- I didn’t know that a cube had six sides.
- I didn’t know all the operas of Puccini.
- When?
- When I was six.
- It is kind of cute.
- The total volume is 875. What is the surface area?
- Can I use a calculator?
- Try not to.
- OK.
- I just had a thought.
- Act normally, it may go away.
- Mark all faces with an x.
- What for?
- Then put a cube on each face with an x.
- What is the volume now?
- And the surface area!
- Vuaw!
- Continue like that. Putting an x on each face and a cube on it.
- And so on and so on?
- Where will it all end!?

Problem source: UK Junior Mathematical Challenge,  May 2011, United Kingdom Mathematics Trust.

### Quote

Monday, May 30th, 2011

The other night I ate at a real nice family restaurant. Every table had an argument going. - George Carlin

### Reflections

Sunday, May 29th, 2011

In English:

### Playful thinking

Saturday, May 28th, 2011

About the programme Just a Minute.

### From a hospital bed

Friday, May 27th, 2011

Hernia operation some time ago.

An inguinal hernia is a protrusion of abdominal-cavity contents through the inguinal canal. They are very common (lifetime risk 27% for men, 3% for women), and their repair is one of the most frequently performed surgical operations. – Wikipedia

Yesterday, I had a bilateral inguinal hernia operation. Since the hospital did not have wifi and/or I didn’t take a long my netbook and, maybe more to the point, I didn’t expect the to stay the night there, I could not post a problem.

Now, I am back home and here comes today’s problem a bit late.

When I came to Spain last fall I was granted membership to Spain’s social security system due to my lack of income. What I had in my bank account, a number between epsilon and delta, was never required information. When I got a job in December I got social securitiy membership as part of my job.

My medical expenses for my hernia problem:

1. Doctor appointment at my medical centre to report the problem. (a)
2. Doctor appointment with specialist to determine if an operation was called for. (b)
3. Hospital doctor appointment to determine the exact character of the problem. Here it was detected that I had two hernias, not one. (c)
4. Hospital blood test, x-ray, heart test for the operation. (d)
5. Hospital operation and room and food for 24 hours. (e)
6. Prescribed medicine to be used after the operation. (f)
7. Removing the metal stitches in a week. (g)
8. Evaluation by the hospital doctor in ten days. (h)

Estimate a-h. Please note that I have no other medical insurance than the one mentioned above.

I shared room with a waiter who was operated for the same problem. We wondered how it was to live hundred or more years back with this kind of problem. The image at the top gives a hint.

### Quote

Friday, May 27th, 2011

Programming is one of the most difficult branches of applied mathematics; the poorer mathematicians had better remain pure mathematicians. - Edsger Dijkstra

### Sigh!

Thursday, May 26th, 2011

“Sometimes I lie awake at night and I ask, “Is life a multiple choice test or is it a true or false test?” … Then a voice comes to me out of the dark and says, “We hate to tell you this but life is a thousand word essay.”
— Charles M. Schulz

Since this blog is far removed from life we ask:

If  x^2  - px – q = 0, where  p  and   q are positive integers, which of the following could not equal  x^3?

1. 4x + 3
2. 8x + 5
3. 8x + 7
4. 10x + 3
5. 26x + 5

Problem source: UK Senior Mathematical Challenge, Organised by the United Kingdom Mathematics Trust.

### Quote

Thursday, May 26th, 2011

The greatest sign of success for a teacher… is to be able to say, “The children are now working as if I did not exist.” - Maria Montessori