OCR MEI Further Mechanics Major Specimen — Question 10 14 marks

Exam BoardOCR MEI
ModuleFurther Mechanics Major (Further Mechanics Major)
SessionSpecimen
Marks14
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicProjectiles
TypeProjectile with bounce or impact
DifficultyStandard +0.3 This is a standard projectile motion question with bounces, requiring routine application of SUVAT equations, coefficient of restitution, impulse-momentum theorem, and geometric series. All techniques are straightforward Further Maths mechanics content with clear signposting and no novel problem-solving required. The multi-part structure and 14 marks indicate moderate length, but each part follows predictable patterns (resolve components, apply e, sum series).
Spec3.02i Projectile motion: constant acceleration model6.03f Impulse-momentum: relation6.03i Coefficient of restitution: e6.03k Newton's experimental law: direct impact

In this question take \(g = 10\). A smooth ball of mass 0.1 kg is projected from a point on smooth horizontal ground with speed 65 m s\(^{-1}\) at an angle \(\alpha\) to the horizontal, where \(\tan\alpha = \frac{3}{4}\). While it is in the air the ball is modelled as a particle moving freely under gravity. The ball bounces on the ground repeatedly. The coefficient of restitution for the first bounce is 0.4.
  1. Show that the ball leaves the ground after the first bounce with a horizontal speed of 52 m s\(^{-1}\) and a vertical speed of 15.6 m s\(^{-1}\). Explain your reasoning carefully. [4]
  2. Calculate the magnitude of the impulse exerted on the ball by the ground at the first bounce. [2]
Each subsequent bounce is modelled by assuming that the coefficient of restitution is 0.4 and that the bounce takes no time. The ball is in the air for \(T_1\) seconds between projection and bouncing the first time, \(T_2\) seconds between the first and second bounces, and \(T_n\) seconds between the \((n-1)\)th and \(n\)th bounces.
    1. Show that \(T_1 = \frac{39}{5}\). [2]
    2. Find an expression for \(T_n\) in terms of \(n\). [2]
  1. According to the model, how far does the ball travel horizontally while it is still bouncing? [3]
  2. According to the model, what is the motion of the ball after it has stopped bouncing? [1]

Question 10:
AnswerMarks Guidance
10(i) P
At projection S
(cid:110)65sin(cid:68)(cid:32)39 and (cid:111)65cos(cid:68)(cid:32)52
After bounce, LM conserved horizontally, so
(cid:111)52
The vertical speed when it bounces is the same
as at projection
AnswerMarks
NEL(cid:110)so 0.4(cid:117)39(cid:32)15.6(cid:110)B1
E1
B1
E1
AnswerMarks
[4]3.3
3.4
3.4
AnswerMarks
1.1Both correct
Accept "horizontal speed not
affected by impact"
Use of NEL
AnswerMarks Guidance
10(ii) (cid:110)0.1(cid:11)15.6(cid:16)((cid:16)39)(cid:12)(cid:32)5.46
A1
AnswerMarks
[2]1.2
1.1Attempt at change in momentum.
Accept sign error
All signs correct
AnswerMarks Guidance
10(iii) (A)
0(cid:32)39T (cid:16)5T2 so T (cid:32) AG
AnswerMarks
1 1 1 5M1
A1
AnswerMarks
[2]3.4
1.1N
Use of appropriate suvat
AnswerMarks Guidance
10(iii) (B)
T (cid:32)(cid:11)0.4(cid:12)n(cid:16)1(cid:117)
AnswerMarks
n 5M1
A1
AnswerMarks
[2]3.1b
2.2aE
Recognise geometric progression
Correct answer
AnswerMarks Guidance
10(iv) 39 a
GP with a(cid:32) and r(cid:32)0.4: S (cid:32)
5 (cid:102) 1(cid:16)r

Total time = 13 s

Total distance travelled while bouncing =

AnswerMarks
676mM1
A1
A1
AnswerMarks
[3]3.1b
I
1.1
C
AnswerMarks
3.2aM
Use of formula
AnswerMarks Guidance
10(v) Carries on after bouncing phase, with
horizontal velocity of 52ms–1E
B1
AnswerMarks
[1]3.5b
Question 10:
10 | (i) | P
At projection S
(cid:110)65sin(cid:68)(cid:32)39 and (cid:111)65cos(cid:68)(cid:32)52
After bounce, LM conserved horizontally, so
(cid:111)52
The vertical speed when it bounces is the same
as at projection
NEL(cid:110)so 0.4(cid:117)39(cid:32)15.6(cid:110) | B1
E1
B1
E1
[4] | 3.3
3.4
3.4
1.1 | Both correct
Accept "horizontal speed not
affected by impact"
Use of NEL
10 | (ii) | (cid:110)0.1(cid:11)15.6(cid:16)((cid:16)39)(cid:12)(cid:32)5.46 | M1
A1
[2] | 1.2
1.1 | Attempt at change in momentum.
Accept sign error
All signs correct
10 | (iii) | (A) | 39
0(cid:32)39T (cid:16)5T2 so T (cid:32) AG
1 1 1 5 | M1
A1
[2] | 3.4
1.1 | N
Use of appropriate suvat
10 | (iii) | (B) | 39
T (cid:32)(cid:11)0.4(cid:12)n(cid:16)1(cid:117)
n 5 | M1
A1
[2] | 3.1b
2.2a | E
Recognise geometric progression
Correct answer
10 | (iv) | 39 a
GP with a(cid:32) and r(cid:32)0.4: S (cid:32)
5 (cid:102) 1(cid:16)r
Total time = 13 s
Total distance travelled while bouncing =
676m | M1
A1
A1
[3] | 3.1b
I
1.1
C
3.2a | M
Use of formula
10 | (v) | Carries on after bouncing phase, with
horizontal velocity of 52ms–1 | E
B1
[1] | 3.5b
In this question take $g = 10$.

A smooth ball of mass 0.1 kg is projected from a point on smooth horizontal ground with speed 65 m s$^{-1}$ at an angle $\alpha$ to the horizontal, where $\tan\alpha = \frac{3}{4}$. While it is in the air the ball is modelled as a particle moving freely under gravity. The ball bounces on the ground repeatedly. The coefficient of restitution for the first bounce is 0.4.

\begin{enumerate}[label=(\roman*)]
\item Show that the ball leaves the ground after the first bounce with a horizontal speed of 52 m s$^{-1}$ and a vertical speed of 15.6 m s$^{-1}$. Explain your reasoning carefully. [4]
\item Calculate the magnitude of the impulse exerted on the ball by the ground at the first bounce. [2]
\end{enumerate}

Each subsequent bounce is modelled by assuming that the coefficient of restitution is 0.4 and that the bounce takes no time. The ball is in the air for $T_1$ seconds between projection and bouncing the first time, $T_2$ seconds between the first and second bounces, and $T_n$ seconds between the $(n-1)$th and $n$th bounces.

\begin{enumerate}[label=(\roman*)]
\setcounter{enumi}{2}
\item \begin{enumerate}[label=(\Alph*)]
\item Show that $T_1 = \frac{39}{5}$. [2]
\item Find an expression for $T_n$ in terms of $n$. [2]
\end{enumerate}
\item According to the model, how far does the ball travel horizontally while it is still bouncing? [3]
\item According to the model, what is the motion of the ball after it has stopped bouncing? [1]
\end{enumerate}

\hfill \mbox{\textit{OCR MEI Further Mechanics Major  Q10 [14]}}