A summer sleigh was designed by an Eskimo for use on the recently unfrozen mud expanses. It possessed two runners each 3m long and 0.01 m
wide, and was to be pulled by six huskies, each of which could exert a thrust of
I 00 N. The Eskimo intended that the total mass of the sleigh and its load should
be 300 kg. Complete adhesion can be expected between the runners and the
mud. Confirm the Eskimo's experience that if the mud was soft the sleigh sank
into it and that when it was firm enough not to sink the dogs couldn't pull it!
Show that his brother's advice 'Make the runners broader' was completely
unsound. Advise him on a remedial measure that would overcome the problem.