The tangential force acting on an object that opposes it from sliding freely on the adjacent surface is called

1. Analyze the question

The question asks for the name of the specific force that acts tangentially (along the surface) to oppose the relative motion or the tendency of motion between two surfaces in contact.

2. Explain the concept

In Physics, when two surfaces are in contact, several forces act on them:

• Weight: The force of gravity pulling an object downwards towards the center of the Earth.
• Normal Force: The force exerted by a surface that supports the weight of an object resting on it, acting perpendicular (at a 90-degree angle) to the surface.
• Upthrust: The upward force exerted by a fluid (liquid or gas) on an object immersed in it.
• Frictional Force: This is the force that acts parallel (tangential) to the surfaces in contact. It always acts in the direction opposite to the intended or actual motion of the object, effectively "resisting" or "opposing" the sliding.

3. Show the solution

• Step 1: Identify the direction of the force. The question specifies a "tangential force." Weight acts vertically, and the Normal force acts perpendicularly. This leaves Frictional force as the only force acting tangentially.
• Step 2: Identify the function of the force. The question specifies that it "opposes it from sliding freely." Friction is defined specifically as the resistive force that opposes relative motion between two surfaces.
• Step 3: Match the definition to the options. Since friction is the only force listed that satisfies both the "tangential" and "opposing" criteria, it is the correct answer.

4. Identify the answer

The correct option is C.

5. Exam Tip

Think of Friction as the "enemy of motion." Whenever you see keywords like "opposes motion," "sliding," "rough surface," or "tangential resistance" in a JAMB question, your mind should immediately go to Frictional Force. Also, remember that the Normal force is always perpendicular (normal) to the surface, while Friction is always parallel to it!