Answer:
Explanation:
We shall apply Doppler's effect here .
original frequency = 79.79 kHz
apparent frequency due to movement of source ( bat ) = 81.63 Hz
Let the velocity of bat be v .
expression for apparent frequency can be given as follows
n =
n is apparent frequency , n₀ is original frequency , V is velocity of light and v is velocity of source of sound
Putting the values
81.63 =
340-v = 332.33
v = 7.67 m /s
velocity of bat is 7.67 m /s .
Answer:
b) 68,9 km/h a) picture
Explanation:
In this problem, since velocity is expressed in km/h and time in minutes, we have to convert either time to hours or velocity to km/min. It is easier to use hours.
Using this formula we pass time to hours:
Now we can plot speed vs time (image 1). The problem says that the driver uses constant speed, so all lines have to be horizontal.
Using the values of the speed we calculate the distance in each interval
Using these values and the fact that she was having lunch in the third one (therefore stayed in the same position), we plot position vs time, using initial position zero (image 2, distance is in km, not meters).
Finally, we compute the average speed with the distance over time:
