The frequency of bird chirping hear by hiran will be 1.77 kHz.
<u>Explanation:</u>
As per Doppler effect, the observer will feel a decrease in the frequency of the receiving signal if the source is moving away from the observer. So the shifted frequency is obtained using the below equation:

Here , c is the speed of sound, Vs is the velocity of source with which it is moving away. f is the original frequency of source and f' is the frequency shift heard by the observer.
As here, f = 1800 Hz, Vs= 6 m/s and c = 343 m/s, then

So, the frequency of bird chirping hear by hiran will be 1.77 kHz.
Newton's First Law Example: Driving a car and hitting something like a tree, the car will stop instantly but you'll keep moving forward. Cars have airbags because of this.
Newton's Second Law Example: It's easier to push a box without anything inside it than a box full of stuff because the box that is full has more mass than the empty one.
Newton's Third Law Example: When air rushes out of a balloon, the opposite reaction is that the balloon will fly around the room.
Answer:
357.6 lb-ft
Explanation:
V = Volume = 8 ft³
dP = Change in pressure = (40-10) = 30 psig
Work done is given by


So, converting to ft-lb

The external work performed during the expansion is 357.6 lb-ft
1 would use less energy. Please vote my answer brainliest! Thanks.
Answer:
b 1.39 m/s²
Explanation:
Given the following data;
Time = 12 seconds
Distance, S = 100 m
Since it's starting from rest, the initial velocity is equal to 0m/s.
To find the acceleration, we would use the second equation of motion;

Where;
S represents the displacement or height measured in meters.
u represents the initial velocity measured in meters per seconds.
t represents the time measured in seconds.
a represents acceleration measured in meters per seconds square.
Substituting into the equation, we have;
100 = 0(12) + ½*a*12²
100 = 0 + 72
100 = 72a
Acceleration, a = 100/72
Acceleration, a = 1.389 ≈ 1.39 m/s²