An object travels North at $6 m/s$ for $8 s$ and then travels South at $3 m/s$ for $7 s$ . What are the object's average speed and velocity?

Question

1315 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-03-17T01:11:31

Average speed $"= 4.6 m/s"$

Average velocity $"= 1.8 m/s along North"$

$"Average speed" = "Total distance"/"Total time"$

$<< V >> = (v_1t_1 + v_2t_2)/(t_1 + t_2)$

$<< V >> = (("6 m/s × 8 s") + ("3 m/s × 7 s"))/("8 s + 7 s") = color(blue)"4.6 m/s"$

$"Average velocity" = "Total displacement"/"Total time"$

$<< vecV >> = (vec(v_1)t_1 + vec(v_2)t_2)/(t_1 + t_2)$

$<< vecV >> = (("6 m/s" (hatj) × "8 s") + ("3 m/s" (-hatj) × "7 s"))/("8 s + 7 s")$

$<< vecV >> = (48hatj - 21hatj)/15\ "m/s"$

$<< vecV >> = (27 hatj)/15\ "m/s" = 1.8hatj\ "m/s" = color(blue)"1.8 m/s along North"$

An object travels North at 6 m/s 6 m/s for 8 s8 s and then travels South at 3 m/s 3 m/s for 7 s 7 s. What are the object's average speed and velocity?