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Simple 1D Kinematics Problem

  • Thread starter Neil6790
  • Start date
  • #1
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Homework Statement


In a historical movie, two knights on horseback start from rest 62 m apart and ride directly toward each other to do battle. Sir George's accleration has a magnitude of 0.21 m/s2, while Sir Alfred's has a magnitude of 0.26 m/s2. How far from Sir George's starting point do the knights collide?

Homework Equations





The Attempt at a Solution


62 - x = (1/2)*(0.21 m/s^2)t^2
62 - x = (1/2)*(0.26 m/s^2)t^2

I was trying to find any velocity or any time but i can't seem to conceive anything logic that would work. Any help would be greatly appreciated.
 

Answers and Replies

  • #2
danago
Gold Member
1,122
4
Try to write equations that give the position of each knight relative to Sir George's starting position at any given time, and then find when they are equal.
 
  • #3
LowlyPion
Homework Helper
3,090
4

Homework Statement


In a historical movie, two knights on horseback start from rest 62 m apart and ride directly toward each other to do battle. Sir George's accleration has a magnitude of 0.21 m/s2, while Sir Alfred's has a magnitude of 0.26 m/s2. How far from Sir George's starting point do the knights collide?

Homework Equations



The Attempt at a Solution


62 - x = (1/2)*(0.21 m/s^2)t^2
62 - x = (1/2)*(0.26 m/s^2)t^2

I was trying to find any velocity or any time but i can't seem to conceive anything logic that would work. Any help would be greatly appreciated.
Almost the right idea.
You need to use different X1 and x2

X1 = 1/2a1t2

X2 = 1/2a2t2

You know that they meet by definition when the time is equal and ...their total distance adds to 62.

Divide the first equation by the second.

You get X1/X2 = a1/a2

and you know X1 + X2 = 62.
 

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