A motorist drives north for 30 min at `85km//h` and then stops for 15 min. He continues travelling north and covers 130 km in 2hours. What is his total displacement and average velocity?

Explanation

`v_(1)=85` kmph, t = 35.0 min, `S_(2)=130` km
`S_(1)="Displacement"=85/60 times 135=49.58` km
`S_(2)=130 km`
a) `S=S_(1)+S_(2)=49.58+130=179.58` km
b) Avg. velocity `=(S_(1)+S_(2)+S_(3))/(t_(1)+t_(2)+t_(3))`
`" "=(49..58+0+130)/(35/60+15/60+2)`
`" "=(179.58 times 60)/(170)=(10774.8)/(170)`
`" "=63.38`
`" "=63.4 km//hr`