Find the magnitude |a| of the vector a = (12, 4).
Vectors: dot & cross product worksheet with answers
1.Easy
a = (12, 4)
|a| =
2.Easy
A force of 470 N acts in the xy-plane at 175° measured anticlockwise from the positive x-axis. Find its x-component Fx.
F = 470 Nθ = 175°
Fx = N
3.Medium
Find the value of k for which the vectors a = (2, 3, 3) and b = (4, −6, k) are perpendicular.
a = (2, 3, 3)b = (4, −6, k)
k =
4.Medium
Find the scalar projection compb a of a = (1, 6, −5) onto b = (−1, −4, 5), that is, the component of a in the direction of b.
a = (1, 6, −5)b = (−1, −4, 5)
compb a =
5.Hard
For a = (1, −4, −4) and b = (−1, 2, 0), find the y-component (a × b)y of the cross product a × b.
a = (1, −4, −4)b = (−1, 2, 0)
(a × b)y =
6.Hard
A force F = (50, 40, 60) N acts at point A(−1, 4, 1). Coordinates are in metres. Find the magnitude |M| of the moment of the force about point O(2, −1, −3).
F = (50, 40, 60) NA(−1, 4, 1) mO(2, −1, −3) m
|M| = N·m
Answer key
- 1. |a| = 12.65
- 2. Fx = −468.2 N
- 3. k = 3.333
- 4. compb a = −7.715
- 5. (a × b)y = 4
- 6. |M| = 548.5 N·m
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