Find the magnitude |a| of the vector a = (−1, −7, −9).
Vectors: dot & cross product worksheet with answers
1.Easy
a = (−1, −7, −9)
|a| =
2.Easy
Find the x-component ûx of the unit vector û that points in the direction of a = (2, −6, −3).
a = (2, −6, −3)
ûx =
3.Medium
Find the value of k for which the vectors a = (6, 4, −5) and b = (k, −2, 1) are perpendicular.
a = (6, 4, −5)b = (k, −2, 1)
k =
4.Medium
Find the value of k for which the vectors a = (−4, −4, 3) and b = (k, −3, 4) are perpendicular.
a = (−4, −4, 3)b = (k, −3, 4)
k =
5.Hard
For a = (6, −2, 4) and b = (−4, −6, −1), find the z-component (a × b)z of the cross product a × b.
a = (6, −2, 4)b = (−4, −6, −1)
(a × b)z =
6.Hard
Find the area A of the triangle with corners A(−1, 1, 3), B(4, 2, −3) and C(3, −2, 1). Coordinates are in metres.
A(−1, 1, 3)B(4, 2, −3)C(3, −2, 1)
A = m²
Answer key
- 1. |a| = 11.45
- 2. ûx = 0.2857
- 3. k = 2.167
- 4. k = 6
- 5. (a × b)z = −44
- 6. A = 15.47 m²
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