[单选题]
A cable car at a ski resork2a/h nne.w 7u- qisiqg(rs*,t cargt0f:gt - 1rfmz) gf8nries skiers a distance of 6.8 km. The cable which moves the car is driven by a pulley with diameter 3.0 m. Assuming no fmg ng)8gt:-ft1f0 z rslippage, how fast must the pulley rotate for the cable car to make the trip in 12 minutes?
A. $9.4 \; rpm$
B. $30 \; rpm$
C. $60 \; rpm$
D. $720 \; rpm$
Post time 2024-1-22 02:51:16