How can I apply Newton's First and Second Law to walking?

Question

I'm thinking the 1st, is the muscles would apply an unblanced force to make us move?
Second-if we're walking and the mass of our body is 130 lbs and we're accelerating at 4 miles per hour, then the force necessary to keep us in motion would be 520

Please give me any feedaback that you could provide-I need to draw diagrams and everything but I do that once I get a feel. I know the two laws, I just don't get how to aplly them

bobpursley · Accepted Answer

I think I would avoid the muscles.

Feet on the ground.
newtons first Law: consider if it were on ice? if frictionless, the person would stay in motion (still). but with friction, the shoes can apply a force on the pavement, and the pavement can apply a force on the shoes, allowing motion.

Second law: when turning direction, shoes apply a sideways force, causing a new acceleration (change of direction).

Third law: for every force the shoe applies, the pavement applies an equal and opposite force.

Ray · Answer

Thanks alot I really appreciate it