Here's why:
* Weight vs. Normal Force: Weight is the force of gravity acting on an object's mass (W = mg, where m is mass and g is acceleration due to gravity). The reaction force, often referred to as the normal force, is the force exerted by a surface perpendicular to the object in contact with it.
* Different Situations:
* Stationary object on a horizontal surface: In this case, the reaction force (normal force) is indeed equal to the weight because the object is at rest, meaning the net force is zero. The normal force counteracts the downward force of gravity.
* Object on an incline: The normal force is not equal to the weight. It is the component of the weight force perpendicular to the incline.
* Object in free fall: When an object falls freely, there is no reaction force acting on it. The object is only under the influence of gravity.
* Object being pushed or pulled: If a force is applied to an object, the reaction force might be different than the weight. The normal force will adjust to counterbalance the combined forces acting on the object.
In summary:
The reaction force is equal to the weight only when the object is at rest on a horizontal surface and no other forces are acting on it. In other scenarios, the reaction force can be different from the weight.
