Problem-Smallest radius of curvature

[petal5]

I've been stuck on this for ages and would appreciate help on how to do it:

On a train, the magnitude of the acceleration experienced by the passengers is limited to 0.050g.If the train is going round a curve at a speed of 220km/hr what's the smallest radius of curvature that the curve can have without exceeding the maximum allowed acceleration on the passengers.

 

[Doc Al]

What have you done so far? Hint: What kind of acceleration is experienced when going around a curve?

 

[petal5]

so far I've attempted to solve using v=r w

 

[Doc Al]

Here's another hint: What have you learned about centripetal acceleration?

 

[petal5]

em,in circular motion direction constantly changes.Centripetal acceleration is the resulting center directed acceleration.

Do I need the formula: a=v^2/r ?

 

[Doc Al]

Do I need the formula: a=v^2/r ?

Yes you do!

When going around a curve, the acceleration is centripetal--that's what they are talking about in this problem.

Be sure to convert everything to standard units before calculating the radius.

 

[petal5]

I'm getting an answer of 74.42km for the radius.Does this sound about right to you?

 

[Doc Al]

How did you arrive at that number?

 

[petal5]

I said 0.050g=v^2/r (taking v to be 61m/s)

 

[Doc Al]

You are forgetting to divide by g, which equals 9.8 m/s^2.

 

[petal5]

Thanks for all your help!So should my equation be: v^2/r=(0.050)(9.80)

 

[Doc Al]

That's right.

 

[OlderDan]

Thanks for all your help!So should my equation be: v^2/r=(0.050)(9.80)

That looks good. Solve the equation for r. You know v. Be careful with your units.