From Mechanics
(Difference between revisions)
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| & {{0}^{2}}={{24\textrm{.}5}^{2}}+2\times (-9\textrm{.}8)\times s \\ | | & {{0}^{2}}={{24\textrm{.}5}^{2}}+2\times (-9\textrm{.}8)\times s \\ |
| & s=\frac{{{24\textrm{.}5}^{2}}}{2\times 9\textrm{.}8}=30\textrm{.}625\text{ m} \\ | | & s=\frac{{{24\textrm{.}5}^{2}}}{2\times 9\textrm{.}8}=30\textrm{.}625\text{ m} \\ |
| + | & \\ |
| + | & \text{OR} \\ |
| + | & \\ |
| + | & s=\frac{1}{2}(24\textrm{.}5+0)\times 2\textrm{.}5=30\textrm{.}625\text{ m} \\ |
| \end{align}</math> | | \end{align}</math> |
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- | OR | |
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- | <p> | |
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- | <math>s=\frac{1}{2}(24\textrm{.}5+0)\times 2.5=30\textrm{.}625\text{ m}</math> | |
- | | |
- | </p> | |
| | (3 marks) | | | (3 marks) |
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Current revision
Solutions
1 (a)
| \displaystyle \begin{align}
& 0=24\textrm{.}5-9\textrm{.}8t \\
& t=\frac{24\textrm{.}5}{9\textrm{.}8}=2\textrm{.}5\text{ seconds} \\
\end{align}
| (3 marks)
|
1 (b)
| \displaystyle \begin{align}
& {{0}^{2}}={{24\textrm{.}5}^{2}}+2\times (-9\textrm{.}8)\times s \\
& s=\frac{{{24\textrm{.}5}^{2}}}{2\times 9\textrm{.}8}=30\textrm{.}625\text{ m} \\
& \\
& \text{OR} \\
& \\
& s=\frac{1}{2}(24\textrm{.}5+0)\times 2\textrm{.}5=30\textrm{.}625\text{ m} \\
\end{align}
| (3 marks)
|
1 (c)
| 61.25 m
| (1 marks)
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| (7 marks)
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2 (a)
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| (1 marks)
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2 (b)
| T = 4900 N
| (1 marks)
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2 (c)
| \displaystyle \begin{align}
& T-4900=500\times 0\textrm{.}6 \\
& T=300+4900=5200\text{ N} \\
\end{align}
| (3 mark)
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2 (d)
| \displaystyle \begin{align}
& 4800-4900=500a \\
& a=\frac{-100}{500}=-0\textrm{.}2\text{ m}{{\text{s}}^{\text{-2}}} \\
& 0\textrm{.}\text{2 m}{{\text{s}}^{-\text{2}}}\quad \text{downwards} \\
\end{align}
| (4 mark)
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| (9 marks)
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3 (a)
| \displaystyle R=5\times 9\textrm{.}8\cos 42{}^\circ =36\textrm{.}4\text{ N}
| (2 mark)
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3 (b)
| \displaystyle F=0\textrm{.}4R=14\textrm{.}6\text{ N}
| (2 marks)
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3 (c)
| \displaystyle \begin{align}
& 5\times 9\textrm{.}8\sin 42{}^\circ -14\textrm{.}6=5a \\
& a=\frac{18\textrm{.}22}{5}=3\textrm{.}64\text{ m}{{\text{s}}^{\text{-2}}} \\
\end{align}
| (3 marks)
|
3 (d)
| \displaystyle \begin{align}
& 2=\frac{1}{2}\times 3\textrm{.}64{{t}^{2}} \\
& t=\sqrt{\frac{4}{3\textrm{.}64}}=1\textrm{.}05\text{ seconds} \\
\end{align}
| (3 marks)
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| (10 marks)
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4 (a)
| \displaystyle \begin{align}
& Q\cos 40{}^\circ =8\times 9\textrm{.}8\sin 40{}^\circ \\
& Q=\frac{8\times 9\textrm{.}8\sin 40{}^\circ }{\cos 40{}^\circ }=65\textrm{.}8\text{ N} \\
\end{align}
| (3 mark)
|
4 (b)
| \displaystyle \begin{align}
& Q\cos 40{}^\circ +F=8\times 9\textrm{.}8\sin 40{}^\circ \\
& Q\sin 40{}^\circ +8\times 9\textrm{.}8\cos 40{}^\circ =R \\
& Q\cos 40{}^\circ =8\times 9\textrm{.}8\sin 40{}^\circ \\
& \text{ }-0\textrm{.}3(Q\sin 40{}^\circ +8\times 9\textrm{.}8\cos 40{}^\circ ) \\
& Q=\frac{8\times 9\textrm{.}8\sin 40{}^\circ -0.\textrm{.}\times 8\times 9\textrm{.}8\cos 40{}^\circ }{\cos 40{}^\circ +0.\times \sin 40{}^\circ } \\
& \text{ }=33\textrm{.}8\text{ N} \\
\end{align}
| (5 marks)
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| (8 marks)
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5 (a)
| \displaystyle \mathbf{v}=(\mathbf{i}+\mathbf{j})+(0\textrm{.}05\mathbf{i}-0\textrm{.}1\mathbf{j})t
| (2 marks)
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5 (b)
| \displaystyle \begin{align}
& -(1+0\textrm{.}05t)=1-0\textrm{.}1t \\
& 0\textrm{.}05t=2 \\
& t=40 \\
\end{align}
| (4 marks)
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| (6 marks)
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