Vector Operations Dot Product Cross Product I Write the foll
Vector Operations (Dot Product Cross Product):
I. Write the following vectors in i, j, k, notation: ( the definitions for the following vectors will be used in Parts II and III)
a=(4, 0, 0) b=(2, 0.5, 0) c=(0, -3, 0)
d=(0, 0, 6) e=(-2, -8, 4) f=(3.5, 2, 7)
II. Compute the following dot products:
a·b a·c c·c
d·e e·d f·a
III. Compute the following cross products:
axb axc axa
dxe exf fxe
Solution
I) a = 4 i^ + 0 j^ + 0 k^
b = 2 i^ + 0.5 j^ + 0 k^
c = 0 i^ - 3 j^ + 0 k^
d = 0 i^ + 0 j^ + 6 k^
e = -2 i^ - 8 j^ + 4 k^
f = 3.5 i^ + 2 j^ + 7 k^
II) a.b = (4 i^ + 0 j^ + 0 k^).(2 i^ + 0.5 j^ + 0 k^) = (8 + 0 + 0) = 8
a.c = (4 i^ + 0 j^ + 0 k^).(0 i^ - 3 j^ + 0 k^) = (0 + 0 + 0) = 0
c.c = (0 i^ - 3 j^ + 0 k^).(0 i^ - 3 j^ + 0 k^) = (0 + 9 +0) = 9
d.e = (0 i^ + 0 j^ + 6 k^).(-2 i^ - 8 j^ + 4 k^) = (0 + 0 + 24) = 24
e.d = (-2 i^ - 8 j^ + 4 k^).(0 i^ + 0 j^ + 6 k^) = (0 + 0 +24) = 24
f.a = (3.5 i^ + 2 j^ + 7 k^).(4 i^ + 0 j^ + 0 k^) = (14 + 0 + 0) = 14
III) a x b = (4 i^ + 0 j^ + 0 k^) x (2 i^ + 0.5 j^ + 0 k^) = 2 k^
a x c = (4 i^ + 0 j^ + 0 k^) x (0 i^ - 3 j^ + 0 k^) = -12 k^
a x a = 0
a x e = (4 i^ + 0 j^ + 0 k^) x (-2 i^ - 8 j^ + 4 k^) = (-16 j^ - 32 k^)
e x f = (-2 i^ - 8 j^ + 4 k^) x (3.5 i^ + 2 j^ + 7 k^) = (-56-8) i^ + (14+14) j^ + (-4+28) k^ =(-64) i^ + (28) j^ +(24)k^
f x e = (3.5 i^ + 2 j^ + 7 k^) x (-2 i^ - 8 j^ + 4 k^) = (8+56) i^ + (-14-14) j^ + (4-28) k^ =(64) i^ + (-28) j^ +(-24)k^