Box pushing and pulling

HOW

1. Try pushing the box while holding it by the handle. Can you manage to move it?
2. Then try to move the box by pulling on the handle. Do you notice a difference?
3. Note that in both cases it is more difficult to start moving the box, and keeping it moving is slightly easier.

WHY

Force is a vector quantity. This means that, in order to describe it fully, it is not enough to give only its value, as in the case of mass, for example. Direction and sense are also important. The box holder determines the distribution of forces in both pushing and pulling. The force you exert when pushing the box can be expressed by two others (see figure). One of these acts downwards, increasing the pressure force of the box on the ground and thus the value of the friction force. When pulling, one of the forces is directed upwards, resulting in less pressure force of the box on the ground and a lower friction force.

In both cases, starting to move the box requires more effort than keeping it moving. When the box is
stationary, you deal with static friction. It has a higher value than dynamic friction. The latter works when
the friction surfaces move relative to each other.