Q3 · 2024 · Paper 2Complex familiar8 marks
QUESTION 3 (8 marks)
A student conducted an experiment to address the following research question: What is the relationship between the angle of inclination and the acceleration from rest down a slope of a object?
Data from the experiment was processed to produce the graph shown.
a)[5 marks]
Determine the magnitude of the frictional force acting on the object when the angle of inclination is . Use the graph and show your working.
b)[3 marks]
Calculate the final velocity of the object when the angle of inclination is . Show your working.
WORKED SOLUTION
8 marksQCAA guide · typeset solution
ANSWER
See worked solution below.
Worked solution
s
sin
in
f
f
et
g
f
n
F
ma
F
a
g
m
F
F
F
mg
θ
θ −
−
−
=
=
=
At sin 45°, on graph a = 5.85 ms-2
(
)
9
5
0
.8
.
5
9
9.8
70
0
.8
7
5.8
7
5
.050
0.053
0.70
0.050
f
f
F
F
×
×
=
×
−
=
=
−
Magnitude of frictional force = 0.054 N
2
2
2
v
u
as
=
+
2
2 5.85
2.4
5.30
0
v
v
=
+
×
×
=
Final velocity = 5.3 m s–1
• recognises the scenario relates to forces
on an inclined plane [1 mark]
• determines the component of weight down
the inclined plane [1 mark]
• identifies from graph the acceleration at
sin 45° [1 mark]
• shows appropriate mathematical
reasoning [1 mark]
• determines the frictional force [1 mark]
• selects appropriate equation/s of motion
[1 mark]
• performs correct substitution [1 mark]
• calculates final velocity of the object
[1 mark]
One QCAA sample method typeset for web; criterion wording is adapted from the official marking guide.
How many marks did you earn?
Compare your working with the guide above.