Question

Which of the following in correct, when a person walks on a rough surface?

• A. The frictional force exerted by the surface keeps him moving
• B. The force which the man exerts on the floor keeps him moving
• C. The reaction of the force which the man exerts on floor keeps him moving
• D. None of the above

Answer 1

The correct option is C The reaction of the force which the man exerts on floor keeps him moving

By Newton's third law of motion, the ground exerts back an equal and opposite force along the line of action of the force we exert on the ground. The vertical component of this reaction force balances our weight (so we do not have any motion perpendicular to the ground), and the horizontal component pushes us forward. So we move

Hence C option is correct