Because it is something someone can be doing for him
The pressure caused by water is: P = P0 + bgh = 1.013×10^5 + 10^3×9.81 × 1.5 = 1.18 atm
It's C i believe. To solve it we just take 20 and divide it by 2. Which gives us the average of 10 m/s
-Steel jelly
Adjust the height of the wooden rod so that it just touches the surface of the water. Switch on the lamp and motor and adjust the speed of the motor until low frequency waves can be clearly observed... Count the number of waves passing a point in ten seconds then Divide by ten to record frequency.