Question

Question #c98a1

Answer 1

Mass and weight are not equivalent on Earth.

Explanation:

Mass and weight are not the same on Earth. Mass can be thought of as a quantity of material substance, whereas weight refers to the force of gravity acting on that mass.

Using the basic relationship `F=ma`, the force of gravity, `F_G` is equal to `mg`, where `m` is the object's mass and `g` is the acceleration due to gravity, a constant equal to `(9.8m)/s^2`.

For example, if an object had a mass of 70kg, it would have a weight equal to `F_G`, where

`70kg*(9.8m)/s^2=686N`

This is approximately 154 pounds.

Note: This value applies on Earth, where `g=(9.8m)/s^2`. The value of "g" on other planets or at different (significant) distances from the earth will vary.

An object's mass (in general) is constant, whereas its weight can fluctuate depending on the gravity it is experiencing. You would have the same mass on the moon, for example, but you would weigh less, because gravity on the moon is approximately 1/6 that on Earth.

Answer 2

No, because weight is the influence of gravity on an object; the mass remains the same.

Explanation:

Mass, is an SI unit for measuring the amount of matter in an object (not to be confused with density). Mass is measured in grams, `g`, however prefixes can be added - kilo, milli, etc.

Weight however, is the influence of the gravitational force on the object. Weight is a force and is measured in Newtons, `N`. Weight is another word for the force of gravity, `F_"g"`.

The object's mass never changes unless you remove the mass. Weight is dependent on the gravitational force and differs. In a dynamics word problem, the force of gravity is assumed as `9.8N [down]`.

For example, if you get a 1kg object and put it on the surface of Earth, it's mass is 1kg, however it's weight is `1kg xx 9.8N [down]`, which is the gravitational force of Earth's gravity.

Get the same object and put it on the Moon, its mass remains the same, but its weight has changed. The gravitational force on the Moon is about, `1/6` the strength of Earth's.

In a real life situation, a scale never measures your mass, but your weight. If you stand on a scale in a normal situation, then your weight is `x` pounds/kilograms, including the `F_"g"`. If you were standing on a scale in an elevator going up, then you are much "heavier", because the `F_"g"` increases with the `F_"N"`, likewise if you were going down, you are "lighter".

Hope this helps :)