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IB Mathematics: Applications and Interpretation HL · AHL 4: Vectors · AHL 4.19
Name Date
Components of a vector Problem set A
Show your formula and your working. Give answers to 3 significant figures.
Difficulty: first skills applying them stretch
Skills
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Find the component of the first vector in the direction of the second.
- (a) \(\mathbf{a}=3\mathbf{i} - 5\mathbf{j}\) in the direction of \(6\mathbf{i} + 2\mathbf{j}\)
- (b) \(\mathbf{a}=\begin{pmatrix}-4\\3\end{pmatrix}\) in the direction of \(\begin{pmatrix}2\\-1\end{pmatrix}\)
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Find the component of the first vector in the direction of the second.
- (a) \(\mathbf{a}=5\mathbf{i} - \mathbf{j} + 4\mathbf{k}\) in the direction of \(2\mathbf{i} + \mathbf{j} - 2\mathbf{k}\)
- (b) \(\mathbf{a}=\begin{pmatrix}1\\6\\-3\end{pmatrix}\) in the direction of \(\begin{pmatrix}4\\-3\\5\end{pmatrix}\)
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Find the component of the first vector perpendicular to the second.
- (a) \(\mathbf{a}=\begin{pmatrix}5\\2\end{pmatrix}\) perpendicular to \(\begin{pmatrix}1\\3\end{pmatrix}\)
- (b) \(\mathbf{a}=\begin{pmatrix}2\\1\\4\end{pmatrix}\) perpendicular to \(\begin{pmatrix}3\\-2\\1\end{pmatrix}\)
In context
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A winch pulls a crate up a ramp with a force \(\mathbf{F}=\begin{pmatrix}7\\2\\-4\end{pmatrix}\) kN. The direction up the ramp is \(\mathbf{d}=\begin{pmatrix}3\\6\\2\end{pmatrix}\).
- (a) Find the component of the force along the ramp.
- (b) Find the component of the force perpendicular to the ramp.
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A drone flies in the direction \(\mathbf{d}=\begin{pmatrix}2\\3\\6\end{pmatrix}\). The wind velocity is \(\mathbf{w}=\begin{pmatrix}9\\-4\\1\end{pmatrix}\) m/s.
- (a) Find the component of the wind in the direction the drone is flying. Is the wind helping or opposing the drone?
- (b) Find the component of the wind perpendicular to the drone's direction.
Stretch
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The vector \(\mathbf{a}=\begin{pmatrix}k\\2\\-1\end{pmatrix}\) has component \(4\) in the direction of \(\mathbf{b}=\begin{pmatrix}2\\3\\6\end{pmatrix}\). Find the value of \(k\).
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Take \(\mathbf{a}=\begin{pmatrix}6\\-3\\2\end{pmatrix}\) and \(\mathbf{b}=\begin{pmatrix}1\\2\\2\end{pmatrix}\). Find the component of \(\mathbf{a}\) in the direction of \(\mathbf{b}\) and perpendicular to \(\mathbf{b}\). Show that the squares of the two components add up to \(|\mathbf{a}|^2\).
jmaths.xyz · AI HL · AHL 4.19 Components of a vector: along and perpendicular