Edexcel M2 2003 June — Question 5 12 marks

Exam BoardEdexcel
ModuleM2 (Mechanics 2)
Year2003
SessionJune
Marks12
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicProjectiles
TypeProjection from elevated point - angle above horizontal
DifficultyStandard +0.3 This is a standard M2 projectile motion question requiring application of SUVAT equations in 2D. Part (a) uses horizontal motion (straightforward), part (b) uses vertical motion with a quadratic (routine), and part (c) finds the angle using velocity components (standard technique). All steps are textbook methods with no novel insight required, making it slightly easier than average.
Spec3.02d Constant acceleration: SUVAT formulae3.02i Projectile motion: constant acceleration model

\includegraphics{figure_3} A ball is thrown from a point 4 m above horizontal ground. The ball is projected at an angle \(\alpha\) above the horizontal, where \(\tan \alpha = \frac{4}{3}\). The ball hits the ground at a point which is a horizontal distance 8 m from its point of projection, as shown in Fig. 3. The initial speed of the ball is \(u\) m s\(^{-1}\) and the time of flight is \(T\) seconds.
  1. Prove that \(uT = 10\). [2]
  2. Find the value of \(u\). [5]
As the ball hits the ground, its direction of motion makes an angle \(\phi\) with the horizontal.
  1. Find \(\tan \phi\). [5]

Part (a)
\((\rightarrow): u \cos \alpha \times T = 8\)
\(u \times \frac{4}{5} \times T = 8\)
AnswerMarks Guidance
\(uT = 10\)M1; M1; A1 (2)
Part (b)
AnswerMarks Guidance
\((\uparrow): -4 = u \sin \alpha T - \frac{1}{2}gT^2\)M1 A1
\(-4 = u \times \frac{3}{5} \times \frac{10}{u} - \frac{1}{2} \times 9.8 \times \left(\frac{10}{u}\right)^2\)M1
\(u = 7\)M1 A1 (7)
\(v_H = u \cos \alpha = \frac{28}{5}\)B1 ft
\(v_V^2 = (-u \sin \alpha) + 2g \times 4\)M1
\(\Rightarrow v_V = 9.8\) (= \(\frac{49}{5}\))A1 ft
\(\tan \phi = \frac{49/5}{28/5} = \frac{7}{4}\)M1 A1 cao (5)
Total: (12 marks)
## Part (a)
$(\rightarrow): u \cos \alpha \times T = 8$

$u \times \frac{4}{5} \times T = 8$

$uT = 10$ | M1; M1; A1 | (2)

## Part (b)
$(\uparrow): -4 = u \sin \alpha T - \frac{1}{2}gT^2$ | M1 A1

$-4 = u \times \frac{3}{5} \times \frac{10}{u} - \frac{1}{2} \times 9.8 \times \left(\frac{10}{u}\right)^2$ | M1

$u = 7$ | M1 A1 | (7)

$v_H = u \cos \alpha = \frac{28}{5}$ | B1 ft

$v_V^2 = (-u \sin \alpha) + 2g \times 4$ | M1

$\Rightarrow v_V = 9.8$ (= $\frac{49}{5}$) | A1 ft

$\tan \phi = \frac{49/5}{28/5} = \frac{7}{4}$ | M1 A1 cao | (5)

**Total: (12 marks)**

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\includegraphics{figure_3}

A ball is thrown from a point 4 m above horizontal ground. The ball is projected at an angle $\alpha$ above the horizontal, where $\tan \alpha = \frac{4}{3}$. The ball hits the ground at a point which is a horizontal distance 8 m from its point of projection, as shown in Fig. 3. The initial speed of the ball is $u$ m s$^{-1}$ and the time of flight is $T$ seconds.

\begin{enumerate}[label=(\alph*)]
\item Prove that $uT = 10$.
[2]
\item Find the value of $u$.
[5]
\end{enumerate}

As the ball hits the ground, its direction of motion makes an angle $\phi$ with the horizontal.

\begin{enumerate}[label=(\alph*)]
\setcounter{enumi}{2}
\item Find $\tan \phi$.
[5]
\end{enumerate}

\hfill \mbox{\textit{Edexcel M2 2003 Q5 [12]}}