Solution 8.1a

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Current revision (12:16, 27 March 2011) (edit) (undo)
 
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Substituting these into the equation
Substituting these into the equation
<math>\mathbf{v}=\mathbf{u}+\mathbf{a}t \ \</math>
<math>\mathbf{v}=\mathbf{u}+\mathbf{a}t \ \</math>
-
gives the velocity of the ball at time <math>t=10 \text{ s }</math> as:
+
gives the velocity of the jet-ski at time <math>t=10 \text{ s }</math> as:
<math>\mathbf{v}=4\mathbf{i}+(0\textrm{.}9\mathbf{i}+0\textrm{.}7\mathbf{j})\times 10</math>
<math>\mathbf{v}=4\mathbf{i}+(0\textrm{.}9\mathbf{i}+0\textrm{.}7\mathbf{j})\times 10</math>
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which gives
which gives
-
<math>\mathbf{v}=13\mathbf{i}+9\mathbf{j} \ \text{ m}{{\text{s}}^{\text{-1}}}</math>
+
<math>\mathbf{v}=13\mathbf{i}+7\mathbf{j} \ \text{ m}{{\text{s}}^{\text{-1}}}</math>

Current revision

In this case we have \displaystyle \mathbf{u}=4\mathbf{i} and \displaystyle \mathbf{a}=0\textrm{.}9\mathbf{i}+0\textrm{.}7\mathbf{j}

Substituting these into the equation \displaystyle \mathbf{v}=\mathbf{u}+\mathbf{a}t \ \ gives the velocity of the jet-ski at time \displaystyle t=10 \text{ s } as:

\displaystyle \mathbf{v}=4\mathbf{i}+(0\textrm{.}9\mathbf{i}+0\textrm{.}7\mathbf{j})\times 10

which gives

\displaystyle \mathbf{v}=13\mathbf{i}+7\mathbf{j} \ \text{ m}{{\text{s}}^{\text{-1}}}