At 10 degrees C a cannon fires a shell at 1324m/s
a) how fast is the shell traveling relative to the soundwave of the explosion?
b) how far away from the cannon is the observer how sees the shell pass by 2s before the sound of the explosion arrives?
I don't understand a and I think that you need some info from a to solve b. So I'm a little bit lost.
Thank you for your help (:
Oops I meant to put it under physics :(
the speed of sound in air is temperature dependent
337.5 m/s 10ºC
To answer these questions, we need to consider the speed of sound and understand the concept of relative velocity.
a) To determine the speed of the shell relative to the soundwave of the explosion, we need to subtract the speed of sound from the speed of the shell.
The speed of sound in air at 10 degrees Celsius is approximately 343 meters per second. So, the relative velocity of the shell with respect to the soundwave can be calculated by subtracting the speed of sound from the speed of the shell:
Relative velocity = Speed of the shell - Speed of sound
Relative velocity = 1324 m/s - 343 m/s
Relative velocity = 981 m/s
Therefore, the shell is traveling 981 meters per second faster than the soundwave of the explosion.
b) Now, to calculate the distance from the cannon to an observer who sees the shell pass by 2 seconds before the sound of the explosion arrives, we need to apply the concept of relative motion.
We know that the speed of sound is approximately 343 m/s. If the sound takes 2 seconds to reach the observer after the shell passes by, we can calculate the distance traveled by the sound wave during this time.
Distance covered by the sound wave = Speed of sound x Time
Distance covered by the sound wave = 343 m/s x 2 s
Distance covered by the sound wave = 686 meters
Now, to find the distance from the cannon to the observer, we need to subtract the distance covered by the sound wave from the total distance traveled by the shell.
Let's assume that the shell travels in a straight line without any change in velocity or deviation. So the distance traveled by the shell is given by:
Distance traveled by the shell = Shell velocity x Time
Distance traveled by the shell = 1324 m/s x 2 s
Distance traveled by the shell = 2648 meters
To find the distance from the cannon to the observer, we subtract the distance covered by the sound wave from the distance traveled by the shell:
Distance = Distance traveled by the shell - Distance covered by the sound wave
Distance = 2648 m - 686 m
Distance = 1962 meters
Therefore, the observer who sees the shell pass by 2 seconds before the sound of the explosion arrives is approximately 1962 meters away from the cannon.