Tuesday Puzzle

4/28/09, 11:00 AM #1

Dan Donaldson
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Registered: 9/17/01

Tuesday Puzzle

A car accelerates at a uniform rate from its starting point. It travels the last quarter of the distance from the starting point to the finish line in 3 seconds. What was the total time from starting point to finish line?

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I have been woodworking for about 25 years now, and would consider myself an enthusiastic amateur. My claim to fame (or infamy) has always been fixing stuff. I spent time in the Air Force in the 60's then went to work as an electronic technician for civil service. I finally got my EE, and being fed up with the civil service nonsense, took a job with Ford Motor Company until I went with the split to Visteon last year. I got interested in music and started playing in a bluegrass band. I wanted a new guitar, and that kind of led me into woodworking. I bought some books, a few tools, and built a guitar. Luckily, I didn't know any better than to try that as a first ever project. I still play it when I get a chance, so it must not be too bad if it can live for over 20 years. After a stint in Mexico for my job, I moved into a new house and built a small shop. Since then I have been collecting tools and skills, probably more of the former than the latter ;-). Finding this site has done more for my skills and enjoyment than anything else. I have learned a lot and really enjoy the friendships that I have made here. I have been married to LOML (Lori) for 32 years now and have 6 kids. When they are all gone, I want to get a 1 bedroom house (so there is not room for them to move back in) and at least a 6 car heated/air conditioned garage for a shop. (Dream on...)

Re: Tuesday Puzzle

4/28/09, 2:14 PM #2

Thomas Skaggs
Guest

Re: Tuesday Puzzle

Dan, sorry but you had to know I would ask this....what kind of car is it? ;-)

Tom

Re: Tuesday Puzzle

4/28/09, 2:39 PM #3

Alex Yeilding
Guest

Same question as Thomas

Specifically, does it run on calculus or Excel? Because I get two different answers :-(

Arrggghhhh!

Re: Tuesday Puzzle

4/28/09, 7:43 PM #4

Alex Yeilding
Guest

Re: Tuesday Puzzle

Approximately 57/8 pi.

Not that that has anything to do with the answer, but it does muddle it for those not wanting to see the answer yet.

I can't believe I had to look up the solution to the quadratic!! :-(

(I was dividing only the sqrt by 2a, not the -b. That's why my solution didn't match Excel, and why my two mathematical approaches didn't agree!)

Re: Tuesday Puzzle

4/28/09, 9:25 PM #5

Dan Donaldson
Member
Offline
5,264 posts

Registered: 9/17/01

Re: Tuesday Puzzle

1927 Duzy (sp?)

- - -

I have been woodworking for about 25 years now, and would consider myself an enthusiastic amateur. My claim to fame (or infamy) has always been fixing stuff. I spent time in the Air Force in the 60's then went to work as an electronic technician for civil service. I finally got my EE, and being fed up with the civil service nonsense, took a job with Ford Motor Company until I went with the split to Visteon last year. I got interested in music and started playing in a bluegrass band. I wanted a new guitar, and that kind of led me into woodworking. I bought some books, a few tools, and built a guitar. Luckily, I didn't know any better than to try that as a first ever project. I still play it when I get a chance, so it must not be too bad if it can live for over 20 years. After a stint in Mexico for my job, I moved into a new house and built a small shop. Since then I have been collecting tools and skills, probably more of the former than the latter ;-). Finding this site has done more for my skills and enjoyment than anything else. I have learned a lot and really enjoy the friendships that I have made here. I have been married to LOML (Lori) for 32 years now and have 6 kids. When they are all gone, I want to get a 1 bedroom house (so there is not room for them to move back in) and at least a 6 car heated/air conditioned garage for a shop. (Dream on...)

Re: Tuesday Puzzle

4/28/09, 9:46 PM #6

Dan Donaldson
Member
Offline
5,264 posts

Registered: 9/17/01

Re: Same question as Thomas

basic formulae (derivatives)

- - -

I have been woodworking for about 25 years now, and would consider myself an enthusiastic amateur. My claim to fame (or infamy) has always been fixing stuff. I spent time in the Air Force in the 60's then went to work as an electronic technician for civil service. I finally got my EE, and being fed up with the civil service nonsense, took a job with Ford Motor Company until I went with the split to Visteon last year. I got interested in music and started playing in a bluegrass band. I wanted a new guitar, and that kind of led me into woodworking. I bought some books, a few tools, and built a guitar. Luckily, I didn't know any better than to try that as a first ever project. I still play it when I get a chance, so it must not be too bad if it can live for over 20 years. After a stint in Mexico for my job, I moved into a new house and built a small shop. Since then I have been collecting tools and skills, probably more of the former than the latter ;-). Finding this site has done more for my skills and enjoyment than anything else. I have learned a lot and really enjoy the friendships that I have made here. I have been married to LOML (Lori) for 32 years now and have 6 kids. When they are all gone, I want to get a 1 bedroom house (so there is not room for them to move back in) and at least a 6 car heated/air conditioned garage for a shop. (Dream on...)

Re: Tuesday Puzzle

4/28/09, 11:41 PM #7

Dan Donaldson
Member
Offline
5,264 posts

Registered: 9/17/01

;-)

- - -

I have been woodworking for about 25 years now, and would consider myself an enthusiastic amateur. My claim to fame (or infamy) has always been fixing stuff. I spent time in the Air Force in the 60's then went to work as an electronic technician for civil service. I finally got my EE, and being fed up with the civil service nonsense, took a job with Ford Motor Company until I went with the split to Visteon last year. I got interested in music and started playing in a bluegrass band. I wanted a new guitar, and that kind of led me into woodworking. I bought some books, a few tools, and built a guitar. Luckily, I didn't know any better than to try that as a first ever project. I still play it when I get a chance, so it must not be too bad if it can live for over 20 years. After a stint in Mexico for my job, I moved into a new house and built a small shop. Since then I have been collecting tools and skills, probably more of the former than the latter ;-). Finding this site has done more for my skills and enjoyment than anything else. I have learned a lot and really enjoy the friendships that I have made here. I have been married to LOML (Lori) for 32 years now and have 6 kids. When they are all gone, I want to get a 1 bedroom house (so there is not room for them to move back in) and at least a 6 car heated/air conditioned garage for a shop. (Dream on...)

Re: Tuesday Puzzle

4/29/09, 11:35 AM #8

Dan Donaldson
Member
Offline
5,264 posts

Registered: 9/17/01

Solution

Here is one method of solving it.

Let the total distance traveled be 1.

Let a be the acceleration.

Let t be the total time traveled.

Basic calculus tells us that the velocity at time t is a*t and the total distance traveled is a*t2/2.

So we know:

(1) 1=a*t2/2 and

(2) 0.75 = a*(t-3)2/2

Solving both sides for a we have :

(3) 2/t2 = 3/(2*(t-3)2)

4*(t-3)2 = 3*t2

t2 - 24t + 36 = 0

t = (24 +/- 4321/2)/2 (11) t = 6*31/2 + 12

Add 3 for the total distance of 12 + 6*31/2 =~ 22.39230485

- - -

I have been woodworking for about 25 years now, and would consider myself an enthusiastic amateur. My claim to fame (or infamy) has always been fixing stuff. I spent time in the Air Force in the 60's then went to work as an electronic technician for civil service. I finally got my EE, and being fed up with the civil service nonsense, took a job with Ford Motor Company until I went with the split to Visteon last year. I got interested in music and started playing in a bluegrass band. I wanted a new guitar, and that kind of led me into woodworking. I bought some books, a few tools, and built a guitar. Luckily, I didn't know any better than to try that as a first ever project. I still play it when I get a chance, so it must not be too bad if it can live for over 20 years. After a stint in Mexico for my job, I moved into a new house and built a small shop. Since then I have been collecting tools and skills, probably more of the former than the latter ;-). Finding this site has done more for my skills and enjoyment than anything else. I have learned a lot and really enjoy the friendships that I have made here. I have been married to LOML (Lori) for 32 years now and have 6 kids. When they are all gone, I want to get a 1 bedroom house (so there is not room for them to move back in) and at least a 6 car heated/air conditioned garage for a shop. (Dream on...)

Tuesday Puzzle

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