Question

Erwin has placed a current meter in 85 fsw/25.9 msw and he must recover it. It weighs 50 lbs/22.7 kg when submerged (net weight). A lift bag is attached and partially inflated until the whole package is neutral. What volume of air was added to the lift bag?

1) 2.79 cu. ft./79 liters
2) 1.78 cu. ft./ 50.5 liters
3) 0.79 cu. ft./ 2.24 liters
4) impossible to determine with the given information

Answer 1

To calculate the volume of air added to the lift bag, we need to determine the buoyant force acting on the meter. We can do this by calculating the weight of the water displaced by the meter and the lift bag. By using the density of water, we can convert the weight of water displaced to the volume of air added to the lift bag.

Step-by-step explanation:

To calculate the volume of air added to the lift bag, we first need to determine the buoyant force acting on the meter. Buoyant force is equal to the weight of the fluid displaced, which in this case is the weight of the water displaced by the meter and the lifted bag.

Using the given information, we can calculate the weight of the water displaced by the meter. The weight of the meter and lift bag, 50 lbs, is equal to the weight of the water displaced.

The volume of water displaced can be calculated using the density of water, which is approximately 62.4 lbs/ft³ or 998.2 kg/m³. Dividing the weight of the water displaced by the density of water, we can find the volume of water displaced, which is equal to the volume of air added to the lift bag.

Therefore, to determine the volume of air added to the lift bag, we can convert the weight of the water displaced to cubic feet or liters.