Even though forces are acting on this box, it remains at rest on the table. which force is represented by vector a.
a. tension
b. kinetic friction
c. dtatic friction
d. air resistance

The representative vector on the object at rest is equal to the static friction of the object.

The given object is at rest because the resultant force on the object is zero.

The representative vector is the resultant of the vectors, this will be resultant of the vertical forces and horizontal forces.

The object will be in equilibrium if the resultant force is zero and the resultant vector will be equal to the static frictional force.

Static frictional force is the force acting on an object that is at rest, this force acts between the object at rest and the resting surface.

Thus, the representative vector on the object at rest is equal to the static friction of the object.  

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C.Static friction

Explanation:

We are given tat a box which is kept on the table.

The box is at rest on the table.

We have to find which force is represented by vector A

We know that

Static friction: it is that force which kept object at rest.It is a type of friction force and  exist  between stationary object and surface on which it is resting.

When some forces acting on the box but the box remain at rest  on the table due to static friction.

The force is represented by vector A is static friction .

C.Static friction

truck y has a greater velocity than truck x.