A motorist drives north for 35.0 minutes at 85 km/h and then stops for 15 minutes.He next continues north,travelling 130 km in 2.00 hours.
(a)What is his total displacement? (b)What is his average velocity?

Explanation

`V_(1)`=85 kmph,t=35.0 min, `S_(2)`=130 km.
`S_(1)`=displacement `=(85)/(60)xx35=49.58` km.
`S_(2)`=130 km.
(a)s=`s_(1)+s_(2)`=49.58+130=179.58km.
(b)Average velocity `V_(ave)=(S_(1)+S_(2)+S_(3))/(t_(1)+t_(2)+t_(3))`
`=(49.5+0+130)/((35)/(60)+(15)/(60)+2)`
`(179.58xx60)/(170)=(10774.8)/(170)`
63.38=63.4 km/hour