Layne walked 700m north for 10s and then walked 500 south for 5s

A) how much distance did she travel?

B)how much displacement did she cover?

C) what is her average speed?

D) what is her average velocity?

A).  Her distance traveled was (700m + 500m) = 1,200 meters

B).  Her displacement was (700m north + 500m south) = 200 meters north

C).  Her average speed = (distance covered) / (time to cover the distance)

Speed = (1,200 meters) / (15 seconds)

Speed = 80 meters/second

(Layne is an incredible walker !  That's about 179 miles per hour.)

(She walks 700m in 10 seconds.  Usain Bolt runs only 100m in 10 seconds.)

D).  Her averge velocity = (displacement) / (time)

Velocity = (200 meters north) / (15 seconds)

Velocity = (13 and 1/3) m/s north

(This is only about 33% faster than Usain Bolt, if he went straight instead of doubling back, and if he could keep it up for 200 meters instead of only 100 meters.)

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s

not too sure thinking all accelerations are pointed down