## anonymous 5 years ago Hi, Could you please help me with the following problem I'm trying to solve without success: John and Jim are racing around a circular track in sports cars. The track has a radius of 400 M. John is leading the race by half a lap and both cars are initially traveling at 60 M/s. Jim than begins to accelerate (acceleration not given). After 50 seconds Jim catches up with John. What was Jim's acceleration ? Thank You

1. jagatuba

Since Jim is 200m behind John (0.5*400m) then covering that distance in 50s is going to be 200m/50s.

2. anonymous

Thanks for your reply. Actually I should have said angular acceleration, not acceleration.

3. jagatuba

Sorry was in another window.

4. jagatuba

Hmmm. This seems like a physics question.

5. jagatuba

So have you seen an equation that goes something like: $a=v ^{2}\div r$

6. jagatuba

or $a=w ^{2}r$

7. anonymous

Yes I have

8. jagatuba

Ok so you are dealing with tangential and angular acceleration with those equations right? Those are the two things that are going to make up your angular acceleration.

9. anonymous

that is correct

10. jagatuba

excuse me velocity not accelleration, but I think you knew what I meant.

11. jagatuba

So you have another equation that goes something like this: $a= 4\pi ^{2}r \div T ^{2}$

12. jagatuba

Since we know that Jim has to increase his velocity by 4m/s to catch up to John in 50 seconds. This would make his tangential velocity 64m/s.

13. jagatuba

We also know the radius of the track 400m.

14. jagatuba

So $a=\left( 64m/s \right)^{2}\div 400m$

15. jagatuba

So the angular acceleration should be $9.30909091m/s ^{2}$

16. jagatuba

I think . . . It's been a loooong time since physics so take that answer with a grain of salt. Check into the physics forum to be sure I'm getting my equations right.

17. anonymous

Thank You anyway. I'll try with the Physics forum