A car heads due west on Interstate 80 going 63.0 km/hr for 2.1 hours. The car then turns and heads exactly northwest on Interstate 42 going 53 km/hr for 3.3 hours. What is the resultant displacement of the car?

Question

yoshi_guy · Answer

So, what I've done so far is to find out the distance traveled for each vector. 63 * 2.1 = 132.3, and 53 * 3.3 = 174.9 km. Since northwest is 45 degrees, the bottom distance before 132.3 km is = to 174.9 * cos(45) = 123.67. I'm not sure where to go from here, though.

jiteshmeghwal9 · Answer

Let the point where car turned be the origin. Then coordinate of final position (-123.67,123.67) and coordinate of initial position are (-132.3, 0)

jiteshmeghwal9 · Answer

Find displacement using distance formula

yoshi_guy · Answer

Is it really that simple though? Doesn't the answer have to do with the pythagoreamn theorem and vector addition?

irishboy123 · Answer

Mmmmm

draw it, maybe?

yoshi_guy · Answer

I already posted a picture of the problem in my second post. I'm just not sure how to find the total displacement sum.

irishboy123 · Answer

are you using the Law of Cosines?

irishboy123 · Answer

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