# Physics

The temperature of the air is 20 Celsius when a tourist drops a coin into a wishing well. She hears the splash 5.30s after she drops the coin. If the air resistance is ignored, how deep is the well?
a) 344m b)332m c)137m d)120m e)0.60m

1. 👍
2. 👎
3. 👁
1. time it takes the coin to fall: h=1/2 g t^2
t=sqrt(2h/g)
time it takes sound to come back: h/vs

given: those times add to 5.2 seconds

5.2=sqrt(2H/g)+h/v
a quadratic: let u=sqrt h so u^2=h
u^2/v+u(sqrt2/g)-5.2=0
u^2+u*vsqrt(2/g)-5.2v=0
calculate v for that temerature, then use the quadratic equation to solve for u (and square it for h)

1. 👍
2. 👎
👤
bobpursley
2. i dont really understand the explanation, so which would be the answer

1. 👍
2. 👎

## Similar Questions

1. ### Physics, fluid mechanics

The temperature of earth atmosphere drops 5°C for every 1km elevation above the earth surface. If the air temperature at ground level is 15°C and 760 mmHg, determine the elevation in m when the pressure is 380 mmHg. Assume the

2. ### Algebra

The folrmula F=9/5c+32 can be used to make temperature conversions with the Celsius ans Fahrenheit temperature scales. F-Fahrenheit temperature C=Celsius temperature Convert 100 degress Fahrenheit to the Celsius temperature scale.

3. ### Math plz HELP!

At 7pm the temperature outside was -5 celsius. What does -5 represent in this situation? A. The change in temperature the last hour B. The number of degrees between 0 Celsius and -5 celsius. C. The temperature at 7pm D. The number

4. ### science

The air temperature is 70 degrees, and the relative humidity is 90%. Which conclusion can be made? A.The dew point temperature is 90% of the air temperature. B.The temperature must rise in order for air to become saturated with

1. ### Physics, Math

A typical volume of a modern hot air balloon is 2500 cubic metres, and a typical maximum temperature of the hot air is 120 degrees Celsius. Given these figures, and an outside air temperature and density of 15 ∘C and 1.225 kg/m3

2. ### writting a program

Speed of Sound. Sound travels through air as a result of collisions between the molecules in the air. The temperature of the air affects the speed of the molecules, which in turn affects the speed of sound. The velocity of sound

3. ### Physics

A boy drops a coin from the top of a tower 50 metres high find the time taken by the coin to reach the ground

4. ### physics

Some say that the hot air balloons with which the Montgolfier brothers performed their first flight had a volume of 1700 cubic metres and could lift 780 kilograms (that includes the balloon, basket and payload). Assume that the

1. ### physics

Suppose that, on a day when the outside temperature is 15 degrees Celsius, we fill a balloon with pure nitrogen gas, of which the molar mass is 28 grams per mole. Now suppose that we want to heat up a second (equally large)

2. ### Math

As dry air moves upward it expands and in doing so cools at a rate of 1 degrees Celsius for each 100 m rise up to about 12 km If the ground temperature is 20 degrees Celsius find an expression for the temperature T as a function

3. ### sphy011

A football game costumarily begins with a coin toss to determine who kicks off. The referee tosses the coin vertically upwards with an initial velocity of 5m/s and it takes 1.02s for it to be in the air. In the absence of air

4. ### chemistry

an average adult inhales a volume of 0.50 liter of air into the lungs with each breath.If the air is warmed from room temperature (20 degree celsius) to body temperature (37 degree celsius),what is the volume of air exhaled?