| Exam Board | OCR MEI |
|---|---|
| Module | Further Mechanics Minor (Further Mechanics Minor) |
| Year | 2019 |
| Session | June |
| Marks | 6 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Work done and energy |
| Type | Lifting objects vertically |
| Difficulty | Moderate -0.8 This is a straightforward application of the work-energy principle (W = mgh) and power formula (P = W/t). Part (a) is direct substitution, part (b) requires setting up a simple inequality, and part (c) asks for qualitative reasoning about energy losses. All parts are routine calculations with no novel problem-solving required, making this easier than average. |
| Spec | 6.02k Power: rate of doing work6.02l Power and velocity: P = Fv |
| Answer | Marks | Guidance |
|---|---|---|
| 1 | (a) | WD = 75ร๐ร16 [=11760 J] |
| Power = (75ร๐ร16)รท5.6 | M1 | 3.3 |
| 2100 W | A1 | 1.1 |
| Answer | Marks | Guidance |
|---|---|---|
| (b) | Power = (๐ร๐ร16)รท5.0 | |
| (๐ร๐ร16)รท5.0 < 2100 | M 1ft | 3.1b |
| M < 67 kg | A1 | 2.2a |
| Answer | Marks |
|---|---|
| (c) | The sand will give way as Gareth runs up the |
| Answer | Marks | Guidance |
|---|---|---|
| the formula mgh | B1 | 2.2b |
Question 1:
1 | (a) | WD = 75ร๐ร16 [=11760 J] | M1 | 1.1a
Power = (75ร๐ร16)รท5.6 | M1 | 3.3
2100 W | A1 | 1.1
[3]
(b) | Power = (๐ร๐ร16)รท5.0
(๐ร๐ร16)รท5.0 < 2100 | M 1ft | 3.1b
M < 67 kg | A1 | 2.2a | 66.9642; accept โค
[2]
(c) | The sand will give way as Gareth runs up the
dune, so he will do more work than given by
the formula mgh | B1 | 2.2b | Oe
[1]1 Dilip and Anna are doing an experiment to find the power at which they each work when running up a staircase at school. The top of the staircase is a vertical distance of 16 m above the bottom of the staircase.
Dilip, who has mass 75 kg , does the experiment first. Anna times him, and finds that he takes 5.6 seconds to run up the staircase.
\begin{enumerate}[label=(\alph*)]
\item Find the average power generated by Dilip as he runs up the staircase.
Anna, who has mass $M \mathrm {~kg}$, then does the same experiment and runs up the staircase in 5.0 seconds. She works out that the average power she has generated is less than the corresponding value for Dilip.
\item Find an inequality satisfied by $M$.
Gareth, who also has mass 75 kg , says that members of his sports club do an exercise similar to this, but they run up a 16 m high sand dune. Gareth can run up the sand dune in 8.4 seconds, but he claims that he generates more power than Dilip.
\item Give a reason why Gareth's claim could be true.
\end{enumerate}
\hfill \mbox{\textit{OCR MEI Further Mechanics Minor 2019 Q1 [6]}}