OCR Further Mechanics 2020 November — Question 1 5 marks

Exam BoardOCR
ModuleFurther Mechanics (Further Mechanics)
Year2020
SessionNovember
Marks5
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicAdvanced work-energy problems
TypeWork done by vector force displacement
DifficultyStandard +0.3 This is a straightforward Further Mechanics question requiring standard application of work = force · displacement, average power = work/time, and the work-energy theorem. While it involves vectors and multiple parts, each step follows directly from formula application with no conceptual challenges or novel problem-solving required. Being Further Maths raises the baseline slightly, but the mechanics are routine.
Spec1.10d Vector operations: addition and scalar multiplication6.02a Work done: concept and definition6.02b Calculate work: constant force, resolved component6.02d Mechanical energy: KE and PE concepts6.02e Calculate KE and PE: using formulae

1 A force of \(\binom { 2 } { 10 } \mathrm {~N}\) is the only horizontal force acting on a particle \(P\) of mass 1.25 kg as it moves in a horizontal plane. Initially \(P\) is at the origin, \(O\), and 5 seconds later it is at the point \(A ( 50,140 )\). The units of the coordinate system are metres.
  1. Calculate the work done by the force during these 5 seconds.
  2. Calculate the average power generated by the force during these 5 seconds. The speed of \(P\) at \(O\) is \(10 \mathrm {~ms} ^ { - 1 }\).
  3. Calculate the speed of \(P\) at \(A\).

Question 1:
AnswerMarks Guidance
1(a)  2   50 
 . 
10 140
AnswerMarks
2×50 + 10×140 = 1500 JM1
A1
AnswerMarks Guidance
[2]1.1
1.1Using WD = F.x
1(b) 1500/5 = 300 W
[1]1.1a Their 1500
1(c) 1 1
×1.25v2 = ×1.25×102 +1500
2 2
AnswerMarks
50 ms–1M1
A11.1
1.1Correct use of work-energy
principle
AnswerMarks Guidance
Not ±Can use their WD for M mark
Alternative methodM1 complete method involving
constant acceleration
formula(e)
 50  8 6
  =5u+ 1. 5 .52 ⇒u=  
140 2 8 8
6 8 14
Then v=   + 5 .5=  
8 8 48
AnswerMarks
v =50 ms–1A1
[2]
M1
complete method involving
constant acceleration
formula(e)
Question 1:
1 | (a) |  2   50 
 . 
10 140
2×50 + 10×140 = 1500 J | M1
A1
[2] | 1.1
1.1 | Using WD = F.x
1 | (b) | 1500/5 = 300 W | B1ft
[1] | 1.1a | Their 1500 | Must be a scalar value
1 | (c) | 1 1
×1.25v2 = ×1.25×102 +1500
2 2
50 ms–1 | M1
A1 | 1.1
1.1 | Correct use of work-energy
principle
Not ± | Can use their WD for M mark
Alternative method | M1 | complete method involving
constant acceleration
formula(e)
 50  8 6
  =5u+ 1. 5 .52 ⇒u=  
140 2 8 8
6 8 14
Then v=   + 5 .5=  
8 8 48
v =50 ms–1 | A1
[2]
M1
complete method involving
constant acceleration
formula(e)
1 A force of $\binom { 2 } { 10 } \mathrm {~N}$ is the only horizontal force acting on a particle $P$ of mass 1.25 kg as it moves in a horizontal plane. Initially $P$ is at the origin, $O$, and 5 seconds later it is at the point $A ( 50,140 )$. The units of the coordinate system are metres.
\begin{enumerate}[label=(\alph*)]
\item Calculate the work done by the force during these 5 seconds.
\item Calculate the average power generated by the force during these 5 seconds.

The speed of $P$ at $O$ is $10 \mathrm {~ms} ^ { - 1 }$.
\item Calculate the speed of $P$ at $A$.
\end{enumerate}

\hfill \mbox{\textit{OCR Further Mechanics 2020 Q1 [5]}}