Solving Rotations Homework: Double Speed vs Halving Radius

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In summary, doubling the speed of the truck will have a greater effect on the magnitude of its acceleration compared to moving to a track with half the radius. This can be proven using the equation a = v^2/R, where doubling the speed results in a 9 m/s^2 acceleration while halving the radius results in a 4.5 m/s^2 acceleration. This is because the velocity is squared in the equation, meaning any changes to the velocity will have a greater impact on the acceleration. This was further confirmed by the fact that if v is replaced by kv, the acceleration becomes k^2 times greater.
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baobao11
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Homework Statement


A truck was driven around a circular track. Which would have a greater effect on the magnitude of its acceleration: moving to a track with half the radius or doubling the speed.
Show proof/sample calculations.

Homework Equations


I'm not quite sure but I went ahead and tried this equation:
a = v^2/R

The Attempt at a Solution


I tried plugging in numbers:
a = v^2/R
v= 15m/s
R = 100m
a= (15^2)/(100) = 2.25 m/s^2

doubled speed:
a= (30^2)/100 = 9 m/s^2

half radius
a = (15^2)/50 = 4.5 m/s^2

If I'm correct, doubling speed will affect the magnitude of the acceleration more than the halved radius, right?
Thank you so much!
 
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  • #2
Yes that is correct since whatever factor you multiply the velocity by, becomes squared as well.

a=v2/r

if 'v' is replaced by 'kv', then a' = k2 (v2/r) = k2a
 
  • #3
rock.freak667 said:
Yes that is correct since whatever factor you multiply the velocity by, becomes squared as well.

a=v2/r

if 'v' is replaced by 'kv', then a' = k2 (v2/r) = k2a


thank you very much for confirming my answer! :smile:
 

FAQ: Solving Rotations Homework: Double Speed vs Halving Radius

How does doubling the speed affect the rotation of an object?

Doubling the speed of an object will result in the rotation rate increasing by a factor of two. This means that the number of rotations per unit time will also double.

What happens to the rotation when the radius is halved?

When the radius is halved, the rotation rate will also be halved. This means that the number of rotations per unit time will decrease by half.

Can you have both double speed and halved radius at the same time?

Yes, it is possible to have both double speed and halved radius at the same time. This would result in the rotation rate remaining the same as the original, since the two effects would cancel each other out.

How do you calculate the rotation rate when given the speed and radius?

The rotation rate can be calculated by dividing the speed by the radius. This will give the number of rotations per unit time.

Does the direction of rotation change when the speed and radius are altered?

No, the direction of rotation remains the same regardless of changes in speed or radius. However, if the speed and radius are both altered in opposite directions, it may result in a change in the direction of rotation.

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