Depends what size your pipe is
Ball valve is usually preferable. full flow with no restriction and a lot easier and faster to turn off when needed.
For Ball valve only,as it gives more full bore flow,unlike wedge block,slow operating in Gate valve.
6.5 gallons, if it is full of water. (if this is a trick question, and the pipe is empty or full of dirt or something, then not 6.5 gallons)
You would measure the water in a bath tub in gallons.
gallons
In Full bore ball valve, The bore dia will be same as internal dia of the pipe.In reduced bore, the bore dia is reduced than the ID of pipe.
A full bottle of water
That depends on what kind of substance is in the gallons.-- If they're full of water, then they weigh about 126.19 tons. (rounded)-- If the gallons are empty, then their weight is zero.
gallons
When it is 3/4 full, it will hold 450 cu ft of water which is 2803 Imperial gallons.
Running a full load of dishes uses 9 to 12 gallons of water. Washing and rinsing the same load by hand takes 20 gallons.
Easy. Fill the 7gal pail to the full mark (7 Gallons) with water. Then pour, from the 7 gallon pail, water into each of the 3 gallon pail up to the full mark. The remaining water left in the 7 gallon is 1 gallon. Pour this gallon into the aquarium. Fill the 7 gallon pail with water, again to the full mark, and then add to the aquarium. 1 Gallon + 7 Gallons = 8 Gallons.