Checking my work - Displacement

[kristy_vincen]

A boat which travels 100km[N], then 40km[N], and finally 80km . The entire trip takes 6.5 hours.
Calculate the total displacement of the boat

d = d2-d1
d = (-80) - 140
d = -220
d = 220km

Just want to make sure this is correct.

Thanks

 

[PhanthomJay]

A boat which travels 100km[N], then 40km[N], and finally 80km . The entire trip takes 6.5 hours.
Calculate the total displacement of the boat

d = d2-d1
d = (-80) - 140
d = -220
d = 220km

Just want to make sure this is correct.

Thanks

Well, no, you are calculating the distance the boat travels (which has magnitude only, a scalar quantity), not the displacement (which is a vector quantity with magnitude and direction).
The boat travels 140 km north, then does a 180 degree turn and heads back traveling 80 km south. Where does it end up? (Draw a sketch). And welcome to PF!

 

[kristy_vincen]

Okay, so, I'm looking for the distance between the start and the finish.

d = d2-d1
d = 140 - 80
d = 60km [N]

Please tell me that's correct!

 

[PhanthomJay]

Yes, the displacement is 60 km [N].