Motion Murder Mystery
A murder has taken place on the ‘Mechanics Express’, a luxury train travelling
through the heart of Europe. The train makes few stops and the suspects have
been narrowed down to a group of six people. Your job is to identify who the
murderer was, who the victim was, when exactly the murder took place, and
finally, why?
Who?
The following 6 people have each made 3 statements about the journey.
The murderer has made 3 errors, the victim made 0 errors.
The other suspects made 1 or 2 errors
Bert says when the train was travelling with
acceleration of 0.5ms-2:
 If the speed was 34ms-1
and 20 seconds later it will
be 44ms-1
 If the speed was 90ms-1
then 1.9km later was
100ms-1.
 After 2minutes speed increased by 10ms-1.
Ellen says with an initial
velocity of 40ms-1:
 if the train accelerated
at 10ms-2 then 2 seconds
later it would be going 60ms-1.
 if the train accelerated at 5ms-2
then after 200 metres it is
travelling at 60 ms-1.
 if the train accelerated at 15ms-2
then 2 seconds later it would be
going 70ms-1
Katie says when the train was
travelling at 20ms-1:
 it reaches a town 1km away after
8minutes 20seconds.
 if the train accelerated at 8 ms-2
until it reaches 22ms-1 it will have been
accelerating for 0.25 seconds.
 it will take 600m at 10ms-2 to reach 40 ms-1.
Sam says in 100seconds:
 The train can accelerate
from 15ms-1 to 19ms-1 at the
rate of 0.04ms-2.
 The train could travel 2.5km
at 2.5ms-1.
 The train will travel 11km while
accelerating from 10 ms-1 at a rate
of 2 ms-2.
Josh says the in 3 minutes
 The train accelerates from 20ms-1
to 50ms-1 at a rate of 10 ms-2.
 The train travels 360m at a
constant speed of 20 ms-1.
 The train can accelerate from 10 ms-1 to 15 ms-1
over a distance of 4500m.
Ben says from rest:
 It will take 2 minutes to
reach 24ms-1 at an
acceleration of 0.2ms-2.
 It takes 1km to reach
50ms-1 at an acceleration
of 1.25ms-2.
 It takes 90 seconds to go 3km at
acceleration of 4ms-2.
When?
The train left the station at 1pm and accelerated uniformly at 0.5ms-2 until it
reached its maximum speed of 60ms-1. It stayed at this constant speed for 50
minutes.
The train then entered a built up area and decelerated uniformly to 40ms-1 over
a period of 88seconds where the train maintained a constant velocity.
The murder took place after the train had travelled 450km from the station.
At what time was this?
Why?
a
3600m/h
b
10m/h
c
1.5km/h
d
9m/min
e
60km/h
f
0.9m/s
g
50m/min
h
15km/min
i
30m/s
j
2.5km/s
k
20m/s
l
4m/s
m
75m/s
n
9m/s
o
21km/h
p
2km/s
q
11km/h
r
0.001m/s
s
300m/s
t
120m/min
u
5km/h
v
1000m/s
w
3km/h
x
4.5m/s
y
9km/h
Put the correct letter in the box below each speed
1.8km/min
0.12km/min
50m/min
60m/min
0.3km/s
3.6km/h
0.54km/min
108km/h
270km/h
120km/min
5000m/h
240m/min
1080km/h
1km/min
0.001km/s
7.2km/h
2m/s
1m/s
25m/min
72km/h
Murderer _________________________
Victim ____________________________
Time _____________________________
Motive ____________________________