Mass or weight: does 1 liter of water have a mass of one kg or does it weigh one kg?

On earth, mass and weight are equivalent, but in physics, it's more correct to use mass (since sometimes objects in physics problems are not on earth!)

So if the object weighs 1 kg, you can use 1 kg as its mass. One newton is the force needed to accelerate 1 kg (mass) at a rate of 1 meter per second^2.

Mass Of 1 Liter Of Water

Mass is the amount of matter that a body contains. The SI unit of mass is kg (kilograms).

On the other hand, weight is the gravititional force acting on that body. This is measured in N (Newtons).

The mass of a body will not change at different altitudes or even in space. However its weight in N will.

Thus 1 litre of water has a MASS of 1 kg.

When talking about weight you use Newtons, not kg. Kg is a unit of mass. The mass of 1 liter of water is 1 kg, since 1 newton = 1 kg times one meter divided by second squared (kg*m/s^2), and in order to calculate weight you just need the mass times the gravity, one liter of water equals 1kg*9.8m/s^2. Therefore one liter of water weighs 9.8 N.

Do not confuse mass and weight. They are not the same.

Mass is a measure of the amount of material, weight a measure of the force on it (due to gravity). So indeed a mass of 1kg has a weight of 1g Newtons (g = acceleration due to gravity).

This is important because you cannot assume g is the same everywhere (its not even exactly the same at all points on Earth, it changes with altitude and it is different in space).

However, for most day to day uses g is almost the same everywhere, so scales are calibrated in kg even though they measure N.

Grams (and kilograms) are units of mass.

Pounds and Newtons are units of force. Weight is a type of force.

The gallon is a unit of volume.

Americans often refer to kg as a unit of force, but we really shouldn't. Technically speaking, that's an error. Though it's not a huge error as long as we're talking about the same gravitational field.

massof 1 kg

In everyday speech, we often use 'weight' when (in physics) we would say 'mass'. In physics, weight is a force expressed in Newtons, calculated by multiplying mass by gravitational acceleration.

Do not be bothered by this; you can continue to say "weight" when you refer to things measured in kilos in everyday life. Just be aware that in physics "weight" has a different meaning, and when talking about kgs or lbs you should say "mass" instead.

I believe water is the base unit for most weights and measures. mass depends on density. for instance oil floats on top of water and it therefore lighter, but I believe that a thick oil actually has more mass due to it's density if the same volume is used. I could be totally wrong though.

Mass Of 1l Of Water