# Problems: Forces

Question 1

The table shows the air resistance on a bicycle at different speeds:

Speed (m/s) | 0 | 1 | 2 | 3 | 4 | 5 |

Friction (N) | 0 | 10 | 30 | 70 | 130 | 200 |

a) Draw a smooth graph of this data.

b) How fast can the cyclist travel if she can exert a forward push of 180 N?

Question 2

Motor bike have a single compression springs on the rear wheels. When the Sophy sits on the bike, she pushes on the rear wheel with 50 percent of her weight. Sophy’s mass is 50 kg, and the spring constant is 60 N/cm. How much does the spring compress when Sophy sits on the bike?