Answer :
Answer:
The boat speed relative to the riverbank is 2.96 m/s
Explanation:
The boat move to the north at 2.7 m/s across the river and the river current is 1.2 m/s to the west, therefore the direction of the boat is perpendicular to the river (90[tex]90^{o}[/tex]).
The boat speed vb = 2.7 m/s
The current speed vc = 1.2 m/s
The formula to calculate the speed of the boad relative to the riverbanks (Vbc), as follow
vbc = [tex]\sqrt{vb^{2}+vc^{2}+2*vb*vc*cos 90^{2} }[/tex]
= [tex]\sqrt{2.7^{2}+1.2^{2} +2* 2.7*1.2*cos 90^{o} }[/tex]
since cos 90 = 0, hence
vbc = [tex]\sqrt{2.7^{2}+1.2^{2} }[/tex]
= 2.96 m/s