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How many seconds will it take before the cars meet?

  • Thread starter Lana Elcic
  • Start date
  • #1
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Homework Statement


Two cars are initially 17.50 km apart on a straight road. If the cars are moving toward each other, car 1 with a speed of 7.50 m/s and car 2 with a speed of 10.40 m/s, how many seconds will it take before the cars meet? Round your answer to three significant figures.

Homework Equations


Don't know

The Attempt at a Solution


Converted to 17,500 m for the distance apart.
I added 7.50 and 10.40; Then I divided 17,500 by 17.9 seconds
=977.65 seconds
 

Answers and Replies

  • #2
Bystander
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You have doubts? Need an organizing/systematic principle?
 
  • #3
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You have doubts? Need an organizing/systematic principle?
I wanted to see if it was right because I didn't use any formulas, I just kinda thought about it.
 
  • #4
haruspex
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I wanted to see if it was right because I didn't use any formulas, I just kinda thought about it.
You have one typo, you wrote 17.9 seconds instead of 17.9 m/s.
If you want to relate your method to a principle, it would be that of relative velocity. Or, equivalently, a change to a different inertial reference frame.
 

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