Circular Motion and calculating time

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Homework Help Overview

The discussion revolves around circular motion, specifically focusing on calculating time using various formulas related to velocity, centripetal force, and acceleration. Participants are exploring the relationships between these concepts and how to apply them to a problem involving a vehicle's motion.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the formula for velocity in circular motion and express uncertainty about calculating time. There is a suggestion to consider alternative formulas that might provide the necessary information. Some participants question the assumptions behind the formulas and seek clarification on the relationships between acceleration, gravity, and the concept of 'g' forces.

Discussion Status

The discussion is active, with participants sharing their attempts at calculations and seeking confirmation on their reasoning. Some guidance has been offered regarding the use of formulas, and there is an ongoing exploration of the implications of acceleration in terms of gravitational force.

Contextual Notes

Participants are working under the constraints of a homework assignment, which may limit the information available to them. There is an emphasis on understanding the relationships between different physical quantities rather than arriving at a final solution.

ForgottenMemo
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Homework Statement



q2.jpg



Homework Equations



Velocity =2PiR/T

Time=2PiR/V

Force Centripetal = MV^2/R

Angular Displacement/Time interval = Average Angular Velocity

Angular Velocity x Radius Of Circle Path = Linear Velocity

Average Angular Acceleration = Change In Angular Acceleration/ Time Interval

Linear Acceleration = Radius of Circular Path x Angular acceleration

Force= Mass x Acceleration



The Attempt at a Solution



How do i calculate time? Once i know that i can use this formula: Velocity =2PiR/T

Is T(Time) = 360 radians?

Im not honestly sure where to start, I've been trying for 4 days now, constantly seeking infomation while at work.
 
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ForgottenMemo said:
How do i calculate time? Once i know that i can use this formula: Velocity =2PiR/T
Wouldn't it perhaps be easier to use a different formula, one in which you know all the required information?
 
Hootenanny said:
Wouldn't it perhaps be easier to use a different formula, one in which you know all the required information?


What do you mean.

1) Transpose the equation again

or

2) there's another formula that i have missed


If so, any hint on where to look.
 
ForgottenMemo said:
What do you mean.

1) Transpose the equation again

or

2) there's another formula that i have missed


If so, any hint on where to look.
The formula is on your list :wink:. You know the centripetal force, the mass and the radius. You want to know the velocity.
 
I so hope this is correct.

Fc= MV^2/R -> Fc x R/M=V^2

Velocity -> (1100x140)/1000 = 154^2 -> \sqrt{154} = 12.4 (m/s ?)


Acceleration -> V^2/R -> 12.4^2/140 -> 1.09 m/s^2


Force Gravity -> M x g -> 1000x9.81 = 9810g
 
Last edited:
ForgottenMemo said:
I so hope this is correct.

Fc= MV^2/R -> Fc x R/M=V^2

Velocity -> (1100x140)/1000 = 154^2 -> \sqrt{154} = 12.4 (m/s ?)

Acceleration -> V^2/R -> 12.4^2/140 -> 1.09 m/s^2
I'm not checking your arithmetic, but your method looks good :approve:
ForgottenMemo said:
Force Gravity -> M x g -> 1000x9.81 = 9810g
I'm guessing by the amount of g acting on the car, they mean how many times the acceleration due to gravity is the acceleration of the car, rather than the actual force. Do you follow?
 
Would i be correct in saying that:

Acceleration x Gravity = The amount of g acting on the vehicle?

1.09 m/s^2 x 9.81 = 10.69
 
ForgottenMemo said:
Would i be correct in saying that:

Acceleration x Gravity = The amount of g acting on the vehicle?

1.09 m/s^2 x 9.81 = 10.69
Not quite. If you accelerate at 1g means you are accelerating at a rate that is equal to the acceleration due to gravity (i.e. 9.81 m.s-2). Similarly, an acceleration of 2g is equivalent to an acceleration of twice that of gravity (i.e. 19.62 m.s-2). That number of g's 'pulled' can be calculated thus:

n = \frac{a}{g}

Do you follow?
 
Last edited:
Ok that would mean that.

Acceleration / Gravity = The amount of g acting on the vehicle

1.09 m/s^2 / 9.81 = 0.1 (g)
 
  • #10
ForgottenMemo said:
Ok that would mean that.

Acceleration / Gravity = The amount of g acting on the vehicle

1.09 m/s^2 / 9.81 = 0.1 (g)
Looks okay to me :approve:
 
  • #11
Hootenanny : It was a pleasure. :biggrin: Thanks for the help.
 
  • #12
ForgottenMemo said:
Hootenanny : It was a pleasure. :biggrin: Thanks for the help.
Not a problem :smile:
 

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