Answer:
Justin's displacement is 12.65 km.
Step-by-step explanation:
Since Justin rides 12 km south, then 4 km west, his displacement can be determined by applying Pythagoras theorem to the sketch of his journey. Let his displacement be represented by s,
[tex]/Hyp/^{2}[/tex] = [tex]/Adj1/^{2}[/tex] + [tex]/Adj2/^{2}[/tex]
[tex]s^{2}[/tex] = [tex]/4/^{2}[/tex] + [tex]/12/^{2}[/tex]
= 16 + 144
[tex]s^{2}[/tex] = 160
⇒ s = [tex]\sqrt{160}[/tex]
= 12.6491
s ≅ 12.65 km
Justin's displacement is 12.65 km.
