Question

A sail boat sails 2 km due East, 5 km 37° South of East and
finally an unknown displacement. If the final displacement
of the boat from the starting point is 6 km due East
(1) 3 km, North
3) 5 km, East
(2) 4 km, South
(4) 3 km, West
​

Answer 1

GIVEN:

the boat sails 2 kilometres due east

X1=2i

then the boat moves 5 km 37°south east

X2(net)

=5cos37 i + ( 5sin 37°- j )

=5cos37 i - 5sin 37°j

=5×4/5 i - 5×3/5 j

=4i -3j

the net displacement is 6km due east

X net=6i

TO FIND:

X3=?

SOLUTION:

X net =X1 +X2+ X3

X3 = X net -X1 - X2

X3= 6i - 2i - (4i - 3j)

X3=6i - 2i -4 i +3 j

X3 = 3 j

ANS IS A )3KM DUE NORTH