What is the difference between mass and weight? Weight is the effect that gravity has on an object. Mass, on the other hand, is the quantity of matter of which an object is composed, regardless of the force of gravity to which it is subject. If you were to move a flagpole on the moon, its weight would be reduced by about 5/6, but its mass would remain the same.
Steps
Method 1 of 2: Convert Weight and Mass
Step 1. You need to know that F (force) = m (mass) * a (acceleration)
This simple equation is all you need to convert weight to mass (or mass to weight, depending on what you want to do). Don't worry about the meaning of the letters - now we explain it to you:
- Weight is a force. You will use Newtons (N) as the unit of weight.
- What you need to find is mass, so we may not know what it's worth at the beginning of the process. After solving the equation, the mass will be expressed in kilograms (kg).
- Gravity is an acceleration. On earth, gravity is a constant, equal to 9.78 m / s2. If you were to measure gravity on other planets, this constant would have a different value.
Step 2. Convert weight to mass, following this example
Let's illustrate the conversion of weight to mass with an example. Let's say you are on earth and you are trying to find out the mass of your car without an engine that weighs 50 kg.
- Take note of the equation. F = m * a.
- Replace the values of variables and constants. We know that weight is a force, which, in our case, is worth 50 N. We also know that Earth's gravity has a value of 9.78 m / s2. Substituted the known values, the equation becomes: 50 N = m * 9.78 m / s2.
- Let's do the necessary operations to solve the equation. We cannot solve the equation by leaving it like this. We need to divide 50 by 9.78 m / s2, so as to isolate m.
- 50 N / 9, 78 m / s2 = 5.11 kg. The machine without motor, which on earth weighs 50 Newtons, has a mass of about 5 kg wherever it is in the universe!
Step 3. Convert mass to weight
Learn how to calculate mass by weight using the following example. Suppose you take a piece of moon rock from the surface of the moon. Let's imagine it has a mass of 1.25 kg. You want to know how much it will weigh when you bring it to earth.
- Take note of the equation. F = m * a.
- Replace the values of variables and constants. We know the mass and the value of the gravitational constant. We know that F = 1.25 kg * 9.78 m / s2.
- Solve the equation. Since the variable whose value we want to calculate is already isolated to the left of the equal, we don't have to make any shifts to solve the equation. We multiply 1.25 kg by 9.78 m / s2, which turns out to be 12, 23 Newton.
Method 2 of 2: Mass Measurement Without Equations
Step 1. Measure the gravitational mass
You can measure the mass using a pan weigher. A pan scale is different from a scale in that it uses a known mass to measure an unknown one, while a normal scale only measures weight.
- Using a triple-arm or double-pan scale allows you to measure the gravitational mass. This measurement is of a static type; it is accurate only when the object is at rest.
- A scale can measure weight and mass. Since the measurement of the weights of the balance varies by the same factor as the object whose mass is to be measured, a balance is able to accurately measure the mass of an object regardless of the specific gravity of the environment.
Step 2. Measure the inertial mass
Inertial mass measurement is a dynamic technique, so it can only be performed when the object is in motion. The inertia of the object is used to quantify the total amount of matter of the object itself.
- To measure an inertial mass, an inertial balance must be used.
- Firmly fix the inertial balance to a table.
- Calibrate the inertial scale by moving the moving part and counting the number of vibrations in a given time, for example 30 seconds.
- Put an object of known mass in the container and repeat the experiment.
- Continue with several objects of known mass to continue calibrating the scale.
- Repeat the experiment with the object of unknown mass.
- Graph all results to find the mass of the last object, the one to be measured.
Advice
- The mass of an object does not vary with the method used to measure it.
- An inertial balance can be used to measure the mass of an object even in an environment without acceleration from gravity.
