YAHWT: Need help understanding a physics question

[yhelothar]

A 65kg man is trying to run across an icy pond. The coefficient of friction between his shoes and the ice is 0.160. What is his maximum acceleration?

So doesn't his maximum acceleration depend on how much leg power he has? How can I find the maxium acceleration without knowing how much force he's putting forwards?

 

[Mo0o]

No, the maximum forward push (acceleration) he can achieve is what friction allows which is .160*65 . If he moves his legs harder than that, his feet will just slip on the ice (kind of like those looney toons cartoon where they're running place)

 

[Armitage]

The Corf of Friction & his weight tells you the maximum forward force he can exert.
Given that and his weight, you can figure out how fast he can accelerate.

 

[yhelothar]

Originally posted by: Mo0o
No, the maximum forward push (acceleration) he can achieve is what friction allows which is .160*65 . If he moves his legs harder than that, his feet will just slip on the ice (kind of like those looney toons cartoon where they're running place)

Ah ok I see what you're saying.
But force of the friction is basically what you said.. .160*65*10(to convert mass to weight in Newtons).
So the maximum forward push cannot exceed the backwards force of friction?

 

[yhelothar]

Anyways I worked this problem out and I got 1.6m/s²
Sounds about right? Seems a bit fast though.

 

[yhelothar]

Anyone?

 

[Mo0o]

It's not the "backwards" force of friction. Friction is actually in your direction of travel. Your feet are directing a force "backwards" and friction give you an opposite and equal reaction, which is what allows you to procede fowards. So in terms of physics, its not your feets that the source of the force moving you forwards but friction.

And i dont think 1.5m/s is that fast, you can do some conversion to find out for sure.