| Exam Board | OCR MEI |
|---|---|
| Module | Further Mechanics A AS (Further Mechanics A AS) |
| Year | 2019 |
| Session | June |
| Marks | 7 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Friction |
| Type | Particle on inclined plane - force parallel to slope |
| Difficulty | Moderate -0.3 This is a standard two-part friction problem on an inclined plane requiring resolution of forces and application of F=μR. Part (a) uses limiting friction with the box about to slip up; part (b) checks if the box slips down when the force is removed. The calculations are straightforward with no conceptual surprises, making it slightly easier than average for A-level mechanics. |
| Spec | 3.03t Coefficient of friction: F <= mu*R model3.03u Static equilibrium: on rough surfaces3.03v Motion on rough surface: including inclined planes |
| Answer | Marks | Guidance |
|---|---|---|
| 3 | (a) | WsinF 70 |
| Answer | Marks |
|---|---|
| 𝜇 = 0.34 | M1* |
| Answer | Marks |
|---|---|
| A1 | 3.3 |
| Answer | Marks |
|---|---|
| 1.1 | Resolving forces parallel to the |
| Answer | Marks |
|---|---|
| R | Condone sign errors, |
| Answer | Marks |
|---|---|
| (b) | The weight component (27.0285…N) |
| Answer | Marks |
|---|---|
| Box does remain in equilibrium | M1 |
| A1 | 3.1b |
| 3.2a | Attempt to compare the weight |
| Answer | Marks |
|---|---|
| www | 130sin12° |
Question 3:
3 | (a) | WsinF 70
F 70130sin 12
R 130cos 12 or R130 1 sin 12 2
42.971...
127.159...
𝜇 = 0.34 | M1*
A1
B1
*M1
A1 | 3.3
1.1
1.1
3.4
1.1 | Resolving forces parallel to the
plane; 3 terms and resolving
essential
soi
F
Using
R | Condone sign errors,
wrong use of g and
cos/sin confusion
42.97148019…
127.1591881…
0.3379345…
[5]
(b) | The weight component (27.0285…N)
is less than the maximum possible frictional
force (42.97…N).
Box does remain in equilibrium | M1
A1 | 3.1b
3.2a | Attempt to compare the weight
component parallel to the plane
and the max frictional force. At
least one correct value seen.
www | 130sin12°
May see 15.9(4) > 0
[2]3 A box weighing 130 N is on a rough plane inclined at $12 ^ { \circ }$ to the horizontal.\\
The box is held at rest on the plane by the action of a force of magnitude 70 N acting up the plane in a direction parallel to a line of greatest slope of the plane.\\
The box is on the point of slipping up the plane.
\begin{enumerate}[label=(\alph*)]
\item Find the coefficient of friction between the box and the plane.
The force of magnitude 70 N is removed.
\item Determine whether or not the box remains in equilibrium.
\end{enumerate}
\hfill \mbox{\textit{OCR MEI Further Mechanics A AS 2019 Q3 [7]}}