Difference between gravity and body weight.

In some cases, the force of gravity and the weight of the object are equal in value. This may give the false impression that there is no difference between these values. Let's try to dispel such assumptions and consider how the force of gravity differs from body weight.

Definition

reflecting the attractive effect of the Earth on an object located close to its surface.

The force of gravity

The weight of the body is considered as the force emanating from the object in relation to its support or upper attachment (for example, a thread or springs).

Body weight

Comparison

To understand what is the difference between gravity and body weight is easier with a specific example. Thus, a book lying on a shelf is subjected to gravity. The latter is applied directly to the body. A similar phenomenon of a gravitational nature is characterized by the interaction of an object and the Earth.

At the same time, the shelf is experiencing the weight of the book. We are talking here about the force that is directed to the support. In our example, the book and the shelf interact, although the reason for the existence of weight is also the attraction of the Earth. If the support is removed, the object will fall freely. In this case, the weight will disappear and only gravity will remain, which constantly acts on the body, but can be compensated by other forces, for example, Archimedean forces.

It is important that both quantities are vector. But the force of gravity for any placement of the body is directed downward. However, in the case of weight, the position in the space of the support is of key importance. Such force is always directed perpendicular to it. The investigated values ​​coincide in vector only under the condition that the support experiencing the weight is in the horizontal plane.

Considering the difference between gravity and body weight, it is worth emphasizing that the second of these quantities depends on whether the object is moving and whether acceleration is observed. Only if the body is at rest or moves evenly, the weight does not differ in value from the force of gravity. Under other conditions, there is no equality between the values. For example, the weight in an elevator picking up speed is different from what it was before the device was sent and coincided with the force of gravity.

Table

Gravity Type of force - weight
Acts directly on the objectPresses on the supporting surface (suspension)
The relationship between the body and the EarthThe relationship between the body and supports
Pointed downwardDirection perpendicular to the support
Permanently presentMay be zero
.