I was going north yesterday evening on I-380 during a winter weather advisory around 40 to 45 mph, and a nice, expensive truck passed us in the left lane probably going 60 to 65 mph.  After 10 or so miles, I passed the Iowa DOT sign that read, "Car crash...Ramp 19".  Sure enough the beautiful truck (which appeared to be new) had exited onto a down ramp and it's entire front end was missing; no ambulance, but the Cedar Rapids police where there with the tow truck.  As the guy passed me, I could not help but think of these equations, even more so after I passed the remains of his truck:



Hyperphysics -- Mass on Frictionless Incline

Having lived in Iowa my entire life I cannot recall the number of incidents of fast pickup trucks passing me at high speed on 100% snow & ice covered roads, and so, please consider this post to be a PSA.  For those who are not interested in kinematics, please note what term is missing in the final equation from the above.

(December 26, 2022 at 9:54 am)Jehanne Wrote: I was going north yesterday evening on I-380 during a winter weather advisory around 40 to 45 mph, and a nice, expensive truck passed us in the left lane probably going 60 to 65 mph.  After 10 or so miles, I passed the Iowa DOT sign that read, "Car crash...Ramp 19".  Sure enough the beautiful truck (which appeared to be new) had exited onto a down ramp and it's entire front end was missing; no ambulance, but the Cedar Rapids police where there with the tow truck.  As the guy passed me, I could not help but think of these equations, even more so after I passed the remains of his truck:



Hyperphysics -- Mass on Frictionless Incline

Having lived in Iowa my entire life I cannot recall the number of incidents of fast pickup trucks passing me at high speed on 100% snow & ice covered roads, and so, please consider this post to be a PSA.  For those who are not interested in kinematics, please note what term is missing in the final equation from the above.

I don't need to know the math when I encounter fucked in the head drivers. Fucked in the head is enough.

(December 26, 2022 at 1:49 pm)brewer Wrote: I don't need to know the math when I encounter fucked in the head drivers. Fucked in the head is enough.

Some aspects of kinematics can (of course) be a bit counterintuitive; for instance, I just learned that narrower tires can be better than thicker, wider ones:

Burt Brothers -- Wide vs. Narrow Tires

I have always assumed that ticker, wider tires were better.  But, greater pressure (force per area) makes sense.

(December 26, 2022 at 9:54 am)Jehanne Wrote: I was going north yesterday evening on I-380 during a winter weather advisory around 40 to 45 mph, and a nice, expensive truck passed us in the left lane probably going 60 to 65 mph.  After 10 or so miles, I passed the Iowa DOT sign that read, "Car crash...Ramp 19".  Sure enough the beautiful truck (which appeared to be new) had exited onto a down ramp and it's entire front end was missing; no ambulance, but the Cedar Rapids police where there with the tow truck.  As the guy passed me, I could not help but think of these equations, even more so after I passed the remains of his truck:



Hyperphysics -- Mass on Frictionless Incline

Having lived in Iowa my entire life I cannot recall the number of incidents of fast pickup trucks passing me at high speed on 100% snow & ice covered roads, and so, please consider this post to be a PSA.  For those who are not interested in kinematics, please note what term is missing in the final equation from the above.

You thought of the wrong equation.

Boru

(December 26, 2022 at 3:52 pm)BrianSoddingBoru4 Wrote:

(December 26, 2022 at 9:54 am)Jehanne Wrote: I was going north yesterday evening on I-380 during a winter weather advisory around 40 to 45 mph, and a nice, expensive truck passed us in the left lane probably going 60 to 65 mph.  After 10 or so miles, I passed the Iowa DOT sign that read, "Car crash...Ramp 19".  Sure enough the beautiful truck (which appeared to be new) had exited onto a down ramp and it's entire front end was missing; no ambulance, but the Cedar Rapids police where there with the tow truck.  As the guy passed me, I could not help but think of these equations, even more so after I passed the remains of his truck:



Hyperphysics -- Mass on Frictionless Incline

Having lived in Iowa my entire life I cannot recall the number of incidents of fast pickup trucks passing me at high speed on 100% snow & ice covered roads, and so, please consider this post to be a PSA.  For those who are not interested in kinematics, please note what term is missing in the final equation from the above.

You thought of the wrong equation.

Boru

Which one would be more correct? Or, a better description?

(December 26, 2022 at 4:02 pm)Jehanne Wrote:

(December 26, 2022 at 3:52 pm)BrianSoddingBoru4 Wrote: You thought of the wrong equation.

Boru

Which one would be more correct?  Or, a better description?

No idea, but a truck on an icy incline isn’t a frictionless situation. If it were, you would never have seen the crashed truck.

Boru

(December 26, 2022 at 4:44 pm)BrianSoddingBoru4 Wrote:

(December 26, 2022 at 4:02 pm)Jehanne Wrote: Which one would be more correct?  Or, a better description?

No idea, but a truck on an icy incline isn’t a frictionless situation. If it were, you would never have seen the crashed truck.

Boru

Ice is a pretty good approximation to a frictionless surface, but, you are correct, ice is not completely without friction. One would also need to factor in air drag. As for the crash, such appeared due to the sudden impact against a concrete siding.