Q&A for How to Calculate the Mass of an Object

For practical purposes, weight and mass are the same thing. Mass is the amount of matter in an object. Mass does not depend on the object's location. Weight, on the other hand, is the measurement of gravitational pull on an object and can change with location.

The three apples weigh a total of 300 g (3 x 100). The two apples weigh a total of 140 g (2 x 70). Therefore, the largest apple weighs 160 g (300 - 140).

If you know the volume and density, use Method 2 above. Otherwise, you'll have to weigh it.

You don't have enough information to find the mass.

Divide 20 by .8.

Dry off the object. If it's too irregular to dry it easily, heat it until all moisture has evaporated.

You can't do it. In a vacuum, all masses accelerate at the same rate (and would hit the ground simultaneously if dropped from the same height at the same time).