A ground observer, for an observation Blimp, sees the flash of an artillery battery 15,400 yards ahead. IF the blimp is directly over the observer at a altitude of 7,000 feet, and sound travels at 1140 feet per second, how long will it be before someone on the blimp will hear the sound of the artillery battery firing? (neglect the tire required for the passage of light).

Tom Vaught

 

My math says roughly 41 seconds. Seems like a long time.

 

I agree I came up with around 41 seconds

 

You guys are full of it. It's 14.838828388625 seconds.

 

40.98885434314051 sec before the blimp hears it.

302tt, you forgot to convert the yards into feet for the distance from the observer.

 

The smart ass answer is: Doesn't matter. The guy in the blimp has already called in the artillery explosion and someone in a tent is panicking.

 

Doh!

 

My math says roughly 41 seconds. Seems like a long time.

Good Job Ryan Mayo CORRECT.

Tom Vaught

 

Wait a minute! If the speed of sound is 1140 fps that's 4.6 seconds per mile. I was told as a child that if you count the time in seconds between a lightning flash to when you hear the thunder then no. of seconds = number of miles away. I have been out by a factor of 4.6 all this time.

 

Old Wives' tale there, 302tt

To be perfectly correct,



"Sound is a vibration that travels through an elastic medium as a wave. The speed of sound describes how far this wave travels in a given amount of time. In dry air at 20 °C (68 °F), the speed of sound is 343 meters per second (1,125 ft/s). This equates to 1,236 kilometers per hour (768 mph) or about one mile in five seconds. This figure for air (or any given gas) increases with gas temperature (equations are given below), but is nearly independent of pressure or density for a given gas."

http://en.wikipedia.org/wiki/Mach_number

"At a temperature of 15 degrees Celsius and at SEA LEVEL level, the speed of sound is 340.3 m/s[2] (1225 km/h, or 761.2 mph, or 1116 ft/s) in the Earth's atmosphere. The speed represented by Mach 1 is not a constant; for example, it is dependent on temperature and atmospheric composition."

"Since the speed of sound increases as the temperature increases, the actual speed of an object traveling at Mach 1 will depend on the fluid temperature around it. Mach number is useful because the fluid behaves in a similar way at the same Mach number. So, an aircraft traveling at Mach 1 at sea level (340.3 m/s, 761.2 mph, 1,225 km/h) will experience shock waves in much the same manner as when it is traveling at Mach 1 at 11,000 m (36,000 ft), even though it is traveling at 295 m/s (654.6 mph, 1,062 km/h, 86% of its speed at sea level)."

You will notice how the difference between a Sea Level "SoS" number was 1,125 ft/s. I gave a number for 7000 ft altitude which was 1140 ft/s.

Tom Vaught

 

NEW ONE:

Two racers are having a race around the world. The first racer will get a head start. The second racer can start when the hands of a "control clock" FIRST COME TOGETHER. IF the "Control Clock" is placed in position and the clock is started when the first racer leaves (at 5 o'clock), how long does the other racer have to wait before he can start the race. (Hours and Minutes required) Extra Points for seconds.

Tom Vaught

 

25min assuming that the small hand doesn't move from the 5 o clock position like it normally would. Or 1500 seconds. If it did move, I would imagine somewhere in the extra 2.5 minute area or so. Maybe around another 150 seconds

 

The small hand will move AND it will take several hours (hint) to be in position for the second racer to start.

Tom Vaught

 

Are you saying all three hands must meet precisely? If so, I think that would only happen at 12:00, so... 7hrs? I don't think that's the answer, as your first post implies minutes and seconds... still thinking on this one.

Lol, I haven't owned a clock with hands in years.

 

3 hours, 43 minutes and 43 seconds

 

Correct but even I don't quite know how they came up with the answer.

Try a different type problem:

The sum of three numbers is 217. If we divide the first number by the second number, the quotient is 5. Division of the second by the third produces the same result. What are the numbers??

Hint: X = the first number

X/5 = the second number

Tom Vaught

 

175, 35, 7

 

Very Good Waterpog!

From a drum of pure gasoline, 5 gallons are drawn off with a pump.
The drum is then refilled by adding lubricating oil and again 5 gallons are drawn off with a pump. IF 36% of this mixture is oil, what is the capacity of the drum?

Tom Vaught

 

13.88 gallon tank.

 

I get the drum capacity to be 18.89 gal. 8.89 gal of gasoline, 5 gal oil at the bottom or 36%, and 5 gal of air at the top.