0

Why?

Now here's the question that got me pondering

A cyclist rounds a bend, The surface of the road is horizontal. The cyclist is forced to lean at an angle of $20^\circ$ to the vertical to 'only just' take the bend successfully. The total sideways frictional force on the tyres is 360 N. The cycle has a mass of 20 kg. What is the mass of the cyclist? (Answer: 78.9 kg)

The trouble I'm having is that I don't understand why the cyclist has to lean to begin with, I tried drawing a free body diagram and equating the torques on the cyclist, but I get 80.9 kg as my answer instead. I also tried resolving the forces like shown here, which curiously also got me 80.9 kg.

ACB
  • 2,588
joshua mason
  • 369

1 Answers1

0

$g = 9.81\ \mathrm{m/s^2}$. You approximated $g = 10$ when converting masses to weights, so your answer for (mass of cyclist plus mass of bike) is $10/9.81$ of the total mass.

ACB
  • 2,588
g s
  • 14,249