- #1

LCSphysicist

- 646

- 161

- Homework Statement
- .

- Relevant Equations
- The friction equations

"A man of mass M stands on a railroad car which is rounding an

unbanked turn of radius R at speed v. His center of mass is height L

above the car, and his feet are distance d apart. The man is facing the

direction of motion. How much weight is on each of his feet?"

I came five equations, and five incognits:

Call the inside side with index i, outside with o

Ni + No = Mg

mi + mo = M

No*d/2 = No*μ*l + Ni*d/2 + Ni*μ*l

I will not develop, but you know that we can came to a answer to both N without μ.

The book came to this equations:

Ni + No = Mg

No*d/2 = No*μ*l + Ni*d/2 + Ni*μ*l

The bold equations is where we desagree, if i could say, i'd say that book's solution is summarized, but justified if d is small in comparation, while my solution is more complete, but in some cases desnecessary. Example, F = Gmm/(r+d)² is the right, but F = m*g is a nice aproximation.

But, i don't know...

unbanked turn of radius R at speed v. His center of mass is height L

above the car, and his feet are distance d apart. The man is facing the

direction of motion. How much weight is on each of his feet?"

I came five equations, and five incognits:

Call the inside side with index i, outside with o

Ni + No = Mg

**Ni*μ = mi*v²/R**

No*μ = mo*v²/(R+d)No*μ = mo*v²/(R+d)

mi + mo = M

No*d/2 = No*μ*l + Ni*d/2 + Ni*μ*l

I will not develop, but you know that we can came to a answer to both N without μ.

The book came to this equations:

Ni + No = Mg

**No*μ + Ni*μ = Mv²/R**No*d/2 = No*μ*l + Ni*d/2 + Ni*μ*l

The bold equations is where we desagree, if i could say, i'd say that book's solution is summarized, but justified if d is small in comparation, while my solution is more complete, but in some cases desnecessary. Example, F = Gmm/(r+d)² is the right, but F = m*g is a nice aproximation.

But, i don't know...