Question

Do we apply a force on the ground while walking? (Yes/No)

Answer 1

Hint: We apply here Newton’s third law of motion, it states that to every action there is an equal and opposite reaction. Walking on the ground is also an example of a resolution of the vector. In which the reaction can be resolved into two components.

Complete step by step solution:
As we know Newton’s third law of motion is relevant for walking because when we put our feet on the ground, we apply force on it. In doing this, the ground actually applies an equal force onto our foot, in the opposite direction, and pushing us in a forward direction. While walking we apply the muscular force towards the ground to overcome the gravitational force applied by the earth.

Let us consider here the example. How a man walks on the ground. Also, we apply here the resolution of the vector.
When a man walks, he pushes the ground with his foot. Let the force of push be ${{\vec F}}$, which makes an angle $\theta $ with the ground. According to Newton’s third law of motion, an equal and opposite reaction $\left( {{{\vec R}}} \right)$ acts on this foot. That is, $\left| {{{\vec F}}} \right| = \left| {{{\vec R}}} \right|.$
Now resolve action $\left( {{{\vec R}}} \right)$ into two components.
i) Horizontal component of $\left( {{{\vec R}}} \right) = {{Rcos}}\theta {{ = Fcos}}\theta {{ (}}\because {{F = R)}}$
ii) Vertical component of $\left( {{{\vec R}}} \right) = {{Rsin}}\theta {{ = Fsin}}\theta $
The vertical component of $\left( {{{\vec R}}} \right)$ balances the weight of the man (W =mg).On the other hand, horizontal component of $\left( {{{\vec R}}} \right)$ helps the man to move in the forward direction.

$\therefore$ Yes, we apply the force while walking on the ground.

Note:
Walking is also possible due to friction when a person is walking; in every step, force is applied to the ground. Because there is friction between the ground and his feet, the ground also applies some force in the opposite direction (due to Newton’s third law of motion) thus walking is possible.