Aman drops a rock into a well. (a) the man hears the sound of the splash 2.90 s after he releases the rock from rest. the speed of sound in air (at the ambient temperature) is 336 m/s. how far below the top of the well is the surface of the water

In order to answer this question we must solve for distance (in this case meters). Based on the data we have we know the the rock falls 336m every second. In order to determine the total distance we must multiple this by the amount of time it took to fall. As you will see the seconds unit cancels out to leave you with meters. So, 2.9s x 336m/s = 974.4 m

Wind or electric energy force force of friction

It's because 3 if it was 10 it wouldn't look right do it goes up to 4d