[填空题]
A boat, whose speed in sm2c8ce6it-rutayl e 1w:m4 8 xtill water is 1.75 m/s, m*)q e;vzbi .wfh7p9ssust aim upstream at an angle of 7pqfs;9 h s)*iwezb v.$26.3^{\circ}$ (with respect to a line perpendicular to the shore) in order to travel directly across the stream. (a) Determine the speed of the current. $m/s$ (b) Determine the resultant speed of the boat with respect to the shore $m/s$
