Ice on a frozen lake will fracture if the normal pressure on it exceeds 40kPa. A skater of mass 60kg wears skates whose blades are each 30cm long and 3.0mm wide.
(i) If the skater stands still with weight equally shared by both skates, calculate the pressure on the ice.
(ii) The skater now glides momentarily balancing on one skate so that the entire weight acts on one blade. Assume the effective contact length of the blade with ice reduces to 15cm while its width remains the same. Calculate the resulting pressure.
(iii) Using your results, determine whether the ice is likely to crack in either situation. Show your reasoning quantitatively.