# Saving Earth from Asteroid

## Homework Statement

A car drives north at 40mi/h for 10mins then turns east and goes 5min at 60mi/hr. Finally it goes southwest at 30mi/h for 6min.
a) determine the displacement
b)average velocity for this trip

## The Attempt at a Solution

x-component: 60mi/hr/60min x 5min = 5mi
y-component: 40mi/h/60min x 10mins = 6.7mi

south-west:
x-component:[(-30mi/hr cos 45°)/60mins]6min = -2.12mi
y-component: [(-30mi/hr sin 45°)/60mins]6min = -2.12mi

a) x-displacement: 5mi + (-2.12mi) = 2.88mi i
y-displacement: 6.7mi + (-2.12mi) = 4.58mi j
b)

tiny-tim
Homework Helper
hi negation!
x-component: 60mi/hr/60min x 5min = 5mi
y-component: 40mi/h/60min x 10mins = 6.7mi

south-west:
x-component:[(-30mi/hr cos 45°)/60mins]6min = -2.12mi
y-component: [(-30mi/hr sin 45°)/60mins]6min = -2.12mi

a) x-displacement: 5mi + (-2.12mi) = 2.88mi i
y-displacement: 6.7mi + (-2.12mi) = 4.58mi j

yes, that looks fine, except i think they expect you to finish by converting into a total distance and a direction

(by "direction" i don't know whether they want an angle, or whether specifying a unit vector would be enough)

(i assume you're ok on b)?)

EDIT: just noticed …

how does this save earth from an asteroid??

Correct me if I am wrong, but displacement means the distance between the starting point and the destination, therefore not the total ground covered.

Yeah, what does the asteroid have to do with it? :O

Correct me if I am wrong, but displacement means the distance between the starting point and the destination, therefore not the total ground covered.

Yeah, what does the asteroid have to do with it? :O

Sorry it was a careless blunder as to the title.
Question has been solved

tiny-tim