jan 08 question 6
a) (-5) ^2 +
^2 = 89 = under square toot = 9.43
b) draw the triangle first to understand and find the angle tanx = 8/5 so x = 57.99= 57.99+ 270 to find the bearing. draw the trinagle to understand it
c) r= r0 + vt
r = (7i-1oJ) + (-5i+8j)*3
r= -8i + 14J
r= r0 + vt
r0 = -8i + 14J because it is moving again from this point
-8i+14j + (ui+vj)*4 = 0 (as it returns to same position vector)
equal postion vector i is the same and j is the same so
-8i + 4ui = 0
u = 2
same you do for J (equal) so v = -3.5
d)
p.v. of P t secs after changing course = (–8i + 14j) + t(2i – 3.5j)
= 7i + …..
Hence total time = 10.5 s
