[填空题]
A 55-kg person riding a bike puts all her weia3meuz f;2 *u sbqf+e1xq; c+jght on each0cg82pml6 jpy pedal when climbing a hill. The pedals rotate in a circle of 0j ygmpl28pc6 radius 17 cm. (a) What is the maximum torque she exerts? $m \cdot N$ (b) How could she exert more torque?