I am not too sure if my answers are correct. Here are the questions:
1. A student standing near a brick wall claps her hands and hears the echo 0.250 s later. If the speed of sound was 340.0 m/s, how far from the wall was she?
For this question I got 85 m.
2. How much faster does sound travel on a hot summer day, 40 degrees celsius than on the coldest day, -40 degrees celsius?
For this question, I got 48.5 m/s (I found the speed of air for each temperature. then I subtracted the speed of air from summer from the one from winter and got 48.5 m/s)
For the questions of echo we take
2d = v•t
So the answer of the first question must be
d = (340)(0.25)/2
d = 42.5 m
Let's go through each question and figure out if your answers are correct.
1. A student standing near a brick wall claps her hands and hears the echo 0.250 s later. If the speed of sound was 340.0 m/s, how far from the wall was she?
To find the distance from the wall, we need to use the formula: distance = speed * time.
In this case, the speed of sound is given as 340.0 m/s, and the time delay is 0.250 s. Plugging in those values into the formula, we get:
distance = 340.0 m/s * 0.250 s
distance = 85.0 m.
So your answer of 85 m is indeed correct.
2. How much faster does sound travel on a hot summer day at 40 degrees Celsius than on the coldest day at -40 degrees Celsius?
To find the difference in sound speed between the hot summer day and the coldest day, we need to know the relationship between temperature and sound speed. The formula used for this is called the "Laplace's law":
speed = sqrt(gamma * R * T)
Where:
- gamma is the heat capacity ratio (approximately 1.4 for air)
- R is the specific gas constant (approximately 287 J/(kg·K) for air)
- T is the temperature in Kelvin (K)
Now, we need to convert the temperatures to Kelvin.
For the hot summer day at 40 degrees Celsius, we add 273 to get 313 K.
For the coldest day at -40 degrees Celsius, we add 273 to get 233 K.
Plugging in these temperatures into the formula, we get:
speed_summer = sqrt(1.4 * 287 J/(kg·K) * 313 K)
speed_winter = sqrt(1.4 * 287 J/(kg·K) * 233 K)
Calculating these values, we find:
speed_summer ≈ 349.14 m/s
speed_winter ≈ 300.88 m/s
To find the difference in speed, we subtract the speed on the coldest day from the speed on the hot summer day:
difference = speed_summer - speed_winter
difference ≈ 349.14 m/s - 300.88 m/s
difference ≈ 48.26 m/s.
So your answer of 48.5 m/s is very close to the correct answer, 48.26 m/s. Great job!
so 1 second would be 340m, 1/4 second is 1/4*340 or 85meters
correct!!!!:)
355m/s-306m/s =49m/s
correct !