| Exam Board | Edexcel |
|---|---|
| Module | M1 (Mechanics 1) |
| Marks | 7 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Momentum and Collisions |
| Type | Calculate impulse from force-time data |
| Difficulty | Moderate -0.8 This is a straightforward M1 mechanics question testing basic impulse-momentum concepts with standard formulas (impulse = change in momentum, F = ma, impulse = Ft). All parts require direct application of well-rehearsed formulas with no problem-solving insight or geometric reasoning needed. The 'show that' in part (c) is routine verification rather than proof. |
| Spec | 6.03f Impulse-momentum: relation |
| Answer | Marks |
|---|---|
| (a) impulse = \(\Delta\) mom = \(800(0 - 15) = -12\,000\) ∴ mag. = 12 000 Ns | M1 A1 |
| (b) \(Ft = 12\,000\), so \(t = \frac{12000}{60000} = 0.2\) s | M1 A1 |
| Answer | Marks | Guidance |
|---|---|---|
| \(0 = 15 + 0.2a\) ∴ \(a = -75\) so decel. = \(75\) ms\(^{-2}\) | M1 | M1 A1 |
**(a)** impulse = $\Delta$ mom = $800(0 - 15) = -12\,000$ ∴ mag. = 12 000 Ns | M1 A1 |
**(b)** $Ft = 12\,000$, so $t = \frac{12000}{60000} = 0.2$ s | M1 A1 |
**(c)** use $v = u + at$ with $v = 0, u = 15, t = 0.2$
$0 = 15 + 0.2a$ ∴ $a = -75$ so decel. = $75$ ms$^{-2}$ | M1 | M1 A1 | (7) |
---In a safety test, a car of mass 800 kg is driven directly at a wall at a constant speed of 15 m s$^{-1}$. The constant force exerted by the wall on the car in bringing it to rest is 60 kN.
\begin{enumerate}[label=(\alph*)]
\item Calculate the magnitude of the impulse exerted by the wall on the car. [2 marks]
\item Find the time it takes for the car to come to rest. [2 marks]
\item Show that the deceleration of the car is 75 m s$^{-2}$. [3 marks]
\end{enumerate}
\hfill \mbox{\textit{Edexcel M1 Q1 [7]}}