The cyclist is going at 10000km per hour not second please. I tried solving it with mv^2/r =0.5mg but is not getting the answer. I am wondering if their answer is wrong. Well, their answer is 4.1m. I am getting r= v^2/.5g. V^2=10000m/3600s=2.77m/s^2=7.67/.5g =1.5m. I don't know how else to solve this question to get their 4.1m answer.

Step 1: Convert 10,000km/hour into m/s.

10,000km/hour x (1000 m/km) x (1 hour / 3600s)

10,000 x 1,000m / 3600s = 2,777m/s

Step 2: Write the relevant equation and solve:

Net Force = Static Friction

Net Force = msN

Net Force = ms x mg

Net Force = (0.5)(10 x mass); (mass is unknown)

Since Net Force = Centripetal Force which = mv^2/R then:

mv^2/R = msN, therefore rearranging for R we get:

v^2 / msg = R

(2,777)^2 / 5 = R

~1.5x10^6 m or 1,500 km

EDIT: Yup, looks like they made a calculation error.