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.
Answer:
Explanation:
Given:
a = 3.10 m/s^2
vf = 12.4 m/s
vi = -6.2 m/s
t = (vf - vi)/a
= (12.4 + 6.2)/3.1
= 6 s
displacement = (vf - vi)*t
= (12.4 + 6.2) * 6
= 111.6 m.
Answer:
a) 919 m
b) 183.8 m
Explanation:
140 calories = 140 * 4186 J/calorie = 586040 J
a)When the hiker climbs a mountain, this energy is converted to potential energy, which has the following formula

where m = 65 kg is the mass, g = 9.81 m/s2 is the gravitational acceleration and h is the height that he climbs


b) If only 20% of food energy goes into mechanical energy, then the actual potential energy is
586040 * 0.2 = 117208
Similarly, the height that he could climbs is

Answer:
a = heart and brain b = lungs
Explanation: