Let us assume you want the flow rate of water from a pipe such as a garden hose . First, the flow rate must be constant . So don't change the position of the tap handle controlling the outward flow. You need 2 things. A clock with a second hand, and a container which has a known fluid volume, such as a kitchen measuring container (say 1/2Litre capacity. ) Now when the second hand is on 12 quickly let all the water flow into the 1/2 Litre container. When the container is perfectly full to the 1/2Litre marking , very quickly remove the container from the water source and at the same instant, take note of how many seconds and/or minutes it took to fill the container. Suppose it took 45 seconds , then the flow rate measured in 'Litre/ Minute' will be 1/2 Litre in 45/60 minutes. This is of course that same as 0.5 Litre per 0.75 minute which equals 0.5 divided by 0.75 Litre/ minute. Answer is therefore 0.6666 Litre/Minute. Flow rate is commonly measured using the units Litre/Minute . It is also often measured in Gallon/Minute, or Litre/Hour or Gallon/Hour. It depends how powerful the flow is . Flow rate of water out of a Reservoir can be measured in megalitres per minute. Sometimes it is measured in Cubic Feet/Minute. The choice of units is your choice but it will always involve a Volume unit and a Time unit.
The mass would not change, only the numbers describing the amount of mass would change.
345 mm is a measure of length. A measure of density would have units of mass divided by volume.
the unit of mass is used to measure the salt.If salt is less in quantity it is measured in mg else it is measured in gm or kg.
A pound is a unit of mass. A centimetre is a unit of length. The two units are therefore incompatible.
Those two units of measure do not convert. One is weight or mass and the other is volume.
length, volume, mass, weight, tempature, time, and rates
Grams
A very good reason is that postal rates are based on their mass - measured in grams. You can measure the mass in widgets and convert to the units used by the postal service, if you so wish.
Tape measure
A flow meter is an instrument used to measure the flow rate of fluids, including liquids with varying viscosities. Flow meters come in various types such as turbine, electromagnetic, ultrasonic, and mass flow meters, which can accurately measure flow rates for a wide range of liquids.
Units of measure are used to measure anything: length or volume, mass or speed, pressure or force etc.
Kilograms.
kilograms
You would use kilograms (kg) to measure someone's mass in metric units.
Grams
grams or other units
The international unit for mass is the kilogram.