If F denotes the contact force, f denotes the frictional force exerted by one surface on the other, `F_(N)` denotes the normal reaction force between the two respectively and none of them are zero, then

Options

A. `Fltf`
B. `F_(N)ltF`
C. `F_(N)gtF`
D. `F_(N)-fltFltF_(N)+f`

Explanation

To solve the problem, we need to understand the relationship between the contact force (F), the frictional force (f), and the normal reaction force (F_N). Here’s the step-by-step solution:

### Step 1: Understand the Forces Acting on the Object
When an object is placed on a surface and a force is applied to it, there are three primary forces to consider:
- The **normal reaction force (F_N)**, which acts perpendicular to the surface.
- The **frictional force (f)**, which opposes the motion of the object.
- The **contact force (F)**, which is the resultant force acting on the object.

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