Are Rolling Resistance Equations for Speed and Acceleration Accurate?

AI Thread Summary
The discussion centers on the accuracy of rolling resistance equations for speed and acceleration, specifically RR = aWS and RR = aWS^2. Participants express confusion over whether rolling resistance is influenced by speed or acceleration, with some asserting it is primarily determined by the formula F_{rr} = μmg. There is acknowledgment of conflicting information regarding the relationship between rolling resistance and speed, prompting suggestions to seek clarification in engineering forums. A request for a clearer explanation of a more complex equation is made, highlighting the need for better understanding amidst the confusion. Overall, the conversation reflects a desire for accurate information on rolling resistance dynamics.
Ideologue
Messages
21
Reaction score
0
Are these simple equations correct?


For rolling resistance force at a given speed:


RR = aWS


For rolling resistance force at a given rate of acceleration:


RR = aWS^2



Where:

RR = rolling resistance

a = coefficient of rolling resistance

W = vehicle weight

S = speed
 
Physics news on Phys.org
As far as I am aware, rolling resistance is not dependant on velocity or acceleration is is simply given by;

F_{rr} = \mu mg

You may be better posting this in an engineering forum though.

~H
 
P \approx \frac{Wa}{r}

W = weight
a = coefficient of rolling resistance
r = radius of wheel
 
Thank you both for your replies.

I have read that rolling resistance does increase with speed, but I have read a lot of confusing and contradicting information on this issue. That is why I now seek clarification. Engineering forum posting is a good idea.

Cyrus’, I am not entirely sure how to use your equation. I admit that I am at a very basic level and I am (due to reading pages of contradicting information from people with negative teaching ability) in a state of high confusion! Please could you explain it and perhaps state where you learned it?
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Back
Top