Circular motion- friction exerted skates/ice and determine friction coefficient

[dani123]

Homework Statement

A 65-kg speed skater with a velocity of 15.0m/s comes into a turn on the track of radius 25.0m.

a) How much friction must be exerted between the skates and the ice to negotiate the turn?

b) Determine the coefficient of friction between the skates and the surface of the ice.

Homework Equations

For part a) I used:
F_c=F_f
v²=μgR
F_f=μmg

For part b) I used:
μ=F_f/F_n

The Attempt at a Solution

For part a) I rearranged the v²=μgR equation to solve for μ=0.918

and then subbed that into the F_f=μmg equation and solved for F_f=585N

For part b) I used μ=F_f/F_n and used m=65kg and g=9.8m/s² to give μ=0.918

If someone could verify that I did this question correctly that would be greatly appreciated! and that my significant figures are being respected! Thank you so much for your help and time :)

 

[tms]

For part a you could have simply used F_f = F_c = m v^2 / r. For part b you could have used the value for \mu you calculated for part a.

 

[dani123]

So are my answers wrong or are they correct but i just found a different way of finding them ? haha

 

[tms]

I didn't check the numbers. As for the physics, see if what you said and what I said are equivalent.

 

[dani123]

yup they do! thanks!