Answer:
A )
Explanation:
This change in frequency observation occur due to doppler effect
if the wave source moves,In the time between one wave peak being emitted and the next, the source will have moved so that the shells will no longer be concentric. The wavefronts will get closer together in front of the source as it travels and will be further apart behind it. (see the graph)
when the person standing still in front of the ambulance, he will observe a <em>higher frequency </em>than before as the source travels towards them.

The pitch we hear depends on the frequency of the sound wave.
A high frequency corresponds to a high pitch
as we hear a higher frequency , it makes the <em>pitch higher</em> too
Answer:
water hydrates the earth's soil....
It’s D.Earths northern hemisphere is tilted toward the sun
The period of the pendulum is 6 seconds.
<h3>What is period?</h3>
Period is the time taken for a simple pendulum to move to(forward) and fro(backward). The s.i unit of period is seconds(s).
Note: When a simple pendulum moves to and fro. it completes one cycle.
From the question, The period of the pendulum is calculated using the formula below.
<h3>Formula</h3>
- T = a+b.............. Equation 1
Where:
- T = Period of the pendulum
- a = Time taken for the pendulum to move forward
- b = Time taken for the pendulum to move backward.
From the question,
Given:
Substitute the values above into equation 1
Hence, The period of the pendulum is 6 seconds.
Learn more about period here: brainly.com/question/21924087