Bulldozer

old school truck dude · March 20, 2012, 03:08:05 PM

A bulldozer is going down the road in a straight line. As you can see, there are many individual track pads that make up the complete tracks. While the dozer is going down the road, the track pads on the top are going 20 miles per hour. HOW FAST ARE THE PADS ON THE BOTTOM GOING? Post your answers!

J.C. · March 20, 2012, 03:24:13 PM

pads that touch the ground dont move

72 Bogger · March 20, 2012, 05:49:21 PM

id say 20 mph but i know thats wrong so i dont know.

Slick · March 20, 2012, 08:53:31 PM

Pads on bottom are going backwards. -20mph

Mudgrunt · March 21, 2012, 12:15:47 AM

fast enough to keep up with the ones on top

Newbie · March 21, 2012, 12:24:13 AM

haha i new it was a trick questions so my guess would be 20 miles per hour.. but after seeing slick saying -20 b/c pads are going backwards i change my answer to his

ProGrade · March 21, 2012, 01:27:10 AM

The pads on the ground are going 0 relative to the ground. The speed of the top pads is irrelevant.

If the bottom pads are going -20 and the top Pads are going 20, your dozer is stuck

black07ss · March 21, 2012, 06:28:41 AM

Quote from: ProGrade on March 21, 2012, 01:27:10 AM
The pads on the ground are going 0 relative to the ground. The speed of the top pads is irrelevant.

If the bottom pads are going -20 and the top Pads are going 20, your dozer is stuck

Haha I'm with prograde on this one!! Lol!

old school truck dude · March 21, 2012, 11:34:37 AM

The pad stops movin when it hits the ground, and it doesnt start movin again until it comes comes back up off of the ground.

wayne w · March 21, 2012, 11:58:44 AM

Quote from: old school truck dude on March 21, 2012, 11:34:37 AM
The pad stops movin when it hits the ground, and it doesnt start movin again until it comes comes back up off of the ground.

x2

HockeyGuy · March 21, 2012, 12:26:43 PM

Quote from: old school truck dude on March 21, 2012, 11:34:37 AM
The pad stops movin when it hits the ground, and it doesnt start movin again until it comes comes back up off of the ground.

x3

ToughBowtieTruck · March 30, 2012, 02:16:16 AM

They're going 20 mph, along with the machine. Every bottom pad becomes a top pad in a few seconds. They are moving forward, because each pad has a new location relative to the ground when it contacts it. Just like a tire. Just because the bottom of the tire is touching the ground doesn't mean it's not moving with the rest of the machine.

The pad never stops moving. It travels along the undercarriage of the bulldozer, relative to the machine movement. It's the illusion of it not moving against the ground that can trick you.

If the bottom pads were traveling at 0 mph then all the other pads connected to it on the top side would be 0 mph as well, a stationary machine. The pads change position on the ground with each rotation, so they are moving.

Question was "How fast are the bottom pads moving?" Not "relative to the ground" or anything like that. If any object changes its place on this earth, 20 miles in one hour, it's moving 20 miles an hour!

old school truck dude · March 30, 2012, 12:05:00 PM

It stops movin when it hits the ground and it dont start movin again till it gets picked back up off the ground. Plain and simple, go watch a dozer move around - the ground aint movin so the pad aint either. The track is constructed of many objects, not just one. Not all of the objects involved in the construction of the track are in constant motion, particularly the pads that are touching the ground. The dozer itself is in motion, but the pads on the ground are not. This is a trick question, theres only one answer

BigFrank · March 30, 2012, 03:01:11 PM

J.C. · March 30, 2012, 05:04:38 PM

If the pads were moving backwards, they would have loss of traction. Same as a car tire. The contact area of the tire that touches the ground doesnt move. If it did you would have a loss of traction.

big red · March 30, 2012, 06:26:38 PM

People way over though this.

4x4xdodgeman · March 30, 2012, 07:40:18 PM

then what the answer!!! Big red

big red · March 30, 2012, 07:46:09 PM

answers "n/a"

Newbie · March 31, 2012, 02:14:21 AM

you guys are crazy. lol

ToughBowtieTruck · March 31, 2012, 01:47:38 PM

Quote from: old school truck dude on March 30, 2012, 12:05:00 PM
It stops movin when it hits the ground and it dont start movin again till it gets picked back up off the ground. Plain and simple, go watch a dozer move around - the ground aint movin so the pad aint either. The track is constructed of many objects, not just one. Not all of the objects involved in the construction of the track are in constant motion, particularly the pads that are touching the ground. The dozer itself is in motion, but the pads on the ground are not. This is a trick question, theres only one answer

Yeah but 20 miles an hour doesn't imply the motion has to be constant. If the pads on the ground, not moving, end up some place else in 20 miles after one hour, they too have "moved" a total of 20 mph