June 2023 Paper 2 Q15
15 In this question use \(g = 9.8\) m s−2
A particle, \(Q\), moves in a straight line across a rough horizontal surface.
A horizontal driving force of magnitude \(D\) newtons acts on \(Q\)
\(Q\) moves with a constant acceleration of 0.91 m s−2
\(Q\) has a weight of 0.65 N
The only resistance force acting on \(Q\) is due to friction.
The coefficient of friction between \(Q\) and the surface is 0.4
Find \(D\) [4 marks]
| Scheme | Marks | AO |
|---|---|---|
| Uses \(m = \dfrac{W}{g}\) PI by sight of AWRT 0.07 | B1 | 1.1b |
| States or uses \(F = \mu R\) PI by sight of \(0.26\) | M1 | 1.1a |
| Forms a three term equation using \(a = 0.91\), their \(F\) and their \(m\) | M1 | 3.3 |
| Forms fully correct equation with all values substituted correctly to obtain \(D\) = 0.32 AWRT 0.32 | A1 | 1.1b |
| (4 marks) |