Biologists have studied the running ability of the northern quoll, a marsupial indigenous to Australia. In one set of experiments, they studied the maximum speed that quolls could run around a curved path without slipping. One quoll was running at 2.4 m/sm/s around a curve with a radius of 1.4 mm when it started to slip. What was the coefficient of static friction between the quoll's feet and the ground in this trial?