Find the magnitude |a| of the vector a = (11, 3).
Vectors: dot & cross product worksheet with answers
1.Easy
a = (11, 3)
|a| =
2.Easy
A force of 160 N acts in the xy-plane at 70° measured anticlockwise from the positive x-axis. Find its x-component Fx.
F = 160 Nθ = 70°
Fx = N
3.Medium
Find the scalar projection compb a of a = (4, −5, 3) onto b = (−3, 6, −2), that is, the component of a in the direction of b.
a = (4, −5, 3)b = (−3, 6, −2)
compb a =
4.Medium
Find the angle θ between the vectors a = (0, 6, −2) and b = (−1, 4, 4), in degrees.
a = (0, 6, −2)b = (−1, 4, 4)
θ = °
5.Hard
A force F = (10, −40, 50) N acts at point A(−1, −1, 3). Coordinates are in metres. Find the y-component My of the moment of the force about point O(2, 1, −2).
F = (10, −40, 50) NA(−1, −1, 3) mO(2, 1, −2) m
My = N·m
6.Hard
For a = (−5, −2, −1) and b = (−1, −6, −4), find the y-component (a × b)y of the cross product a × b.
a = (−5, −2, −1)b = (−1, −6, −4)
(a × b)y =
Answer key
- 1. |a| = 11.4
- 2. Fx = 54.72 N
- 3. compb a = −6.857
- 4. θ = 63.87 °
- 5. My = 200 N·m
- 6. (a × b)y = −19
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