| Exam Board | Edexcel |
|---|---|
| Module | M2 (Mechanics 2) |
| Year | 2003 |
| Session | January |
| Marks | 8 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Work done and energy |
| Type | Acceleration from power and speed |
| Difficulty | Moderate -0.3 This is a straightforward M2 mechanics question testing standard applications of power-force-velocity relationships and the work-energy principle. Part (a) requires P=Fv to find driving force, then F=ma with resistance; part (b) is direct application of work-energy theorem. The calculations are routine with no conceptual challenges beyond knowing the standard formulas, making it slightly easier than average. |
| Spec | 3.03d Newton's second law: 2D vectors6.02a Work done: concept and definition6.02l Power and velocity: P = Fv |
A car of mass 1000 kg is moving along a straight horizontal road with a constant acceleration of $f$ m s$^{-2}$. The resistance to motion is modelled as a constant force of magnitude 1200 N. When the car is travelling at 12 m s$^{-1}$, the power generated by the engine of the car is 24 kW.
\begin{enumerate}[label=(\alph*)]
\item Calculate the value of $f$. [4]
\end{enumerate}
When the car is travelling at 14 m s$^{-1}$, the engine is switched off and the car comes to rest, without braking, in a distance of $d$ metres. Assuming the same model for resistance,
\begin{enumerate}[label=(\alph*)]
\setcounter{enumi}{1}
\item use the work-energy principle to calculate the value of $d$. [3]
\item Give a reason why the model used for the resistance to motion may not be realistic. [1]
\end{enumerate}
\hfill \mbox{\textit{Edexcel M2 2003 Q2 [8]}}