6. Borax was mined in Death Valley, California, during the nineteenth century. It
was transported from the valley by massive wagons, each pulled by a team of
21 mules. Suppose each mule's power output was 746 W (about 1 hp). If in a
certain time interval the total work done by the team on the wagon was
2.35x 10' J, how long was that interval of time?