Two forces act at a point in the xy-plane: F₁ = 120 N at 5° and F₂ = 20 N at 155°, both measured anticlockwise from the positive x-axis. Find the direction φ of their resultant, measured anticlockwise from the positive x-axis (between 0° and 360°).
Vectors: dot & cross product worksheet with answers
1.Easy
F1 = 120 N, θ1 = 5°F2 = 20 N, θ2 = 155°
φ = °
2.Easy
Find the y-component ûy of the unit vector û that points in the direction of a = (4, 4, 4).
a = (4, 4, 4)
ûy =
3.Medium
Find the scalar projection compb a of a = (6, −4, −6) onto b = (1, −3, −5), that is, the component of a in the direction of b.
a = (6, −4, −6)b = (1, −3, −5)
compb a =
4.Medium
Find the value of k for which the vectors a = (4, 1, −4) and b = (6, −2, k) are perpendicular.
a = (4, 1, −4)b = (6, −2, k)
k =
5.Hard
Find the volume V of the parallelepiped whose edges from one corner are a = (1, −2, −1), b = (−5, 4, −5) and c = (0, 4, 1).
a = (1, −2, −1)b = (−5, 4, −5)c = (0, 4, 1)
V =
6.Hard
For a = (−4, −3, 1) and b = (−6, 0, −1), find the x-component (a × b)x of the cross product a × b.
a = (−4, −3, 1)b = (−6, 0, −1)
(a × b)x =
Answer key
- 1. φ = 10.56 °
- 2. ûy = 0.5774
- 3. compb a = 8.113
- 4. k = 5.5
- 5. V = 34
- 6. (a × b)x = 3
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