[填空题]
A 55-kg person riding a bike puts9h* s8v4z;1xw8zazobkw kb j0 all her weight on each pedal when cl6gmz f2c*a,c;z r0mx rimbing a hill. The pe;mc6 czxgraf m0 ,r2z*dals rotate in a circle of radius 17 cm. (a) What is the maximum torque she exerts? $m \cdot N$ (b) How could she exert more torque?