Question

A student drives 5.5 km from his home to school in 35 minutes but makes the return trip in only 25 minutes. What are the average speed and average velocity for

A. Each half of the round trip

B. Total trip

Answer 1

A. avr speed : $v_{avr}=\Delta s/\Delta t=5500/(35\cdot60)=2.62\ (m/s)$

avr velocity: $v_{avr}=\Delta r/\Delta t=5500/(35\cdot60)=2.62\ (m/s)$

avr speed : $v_{avr}=\Delta s/\Delta t=5500/(25\cdot60)=3.67\ (m/s)$

avr velocity: $v_{avr}=\Delta r/\Delta t=5500/(25\cdot60)=3.67\ (m/s)$

B. avr speed : $v_{avr}=\Delta s/\Delta t=2\cdot5500/((35+25)\cdot60)=3.06\ (m/s)$

avr velocity : $v_{avr}=\Delta r/\Delta t=0/((35+25)\cdot60)=0\ (m/s)$