Please help me
Please answer correctly
Will give the brainliest!
Urgent !!!​

Explanation:

B)

Look at the variation in times. It makes quite a difference each time the experiment is repeated. Added to that, there is no mention about what they did about reaction time which would alter the results considerably.

C)

Get the average for the time.

Time for each trial

Total Time = 2.95+3+2.90+3.20+2.95 = 15

Average Time = 15/5 = 3.00 seconds

Speed of Sound = distance divided by time

Speed of Sound = 500 * 2 / 3 = 333 meters / second

D)

Yes. The girl has made a very astute observation. Remember that sound is a wave and it depends on the media it is in. If the media is moving, then the speed of sound will have to take into consideration how fast the media is going and whether the sound is travelling with the media or against it or at some angle to the direction of the sound wave.

To help you understand this question, you probably have taken problems were a boat is travelling up stream or down stream and the water is flowing. The speed is calculated as v_boat + river speed and v_boat - river speed.  

If you haven't seen this problem get, you will.

because if the tool that you are using is not balanced it there would be false mass.