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# M1 connected bodies

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1. https://2802a3b1a650824d2586fd3336bd...%20Edexcel.pdf

question 7 part c

my diagram has a big 800kg square on the right and a stick in the middle connected to a 200 kg square
on the 800kg square , it has 400N and FN and tension of 100N in the towbar all going left
on the 200kg square it has 100N in the towbar and just 200N going to the left

calculating for the acceleration i used f=ma on the trailer(200kg square)
200-100=200a defining positive as left
thus a=0.5ms^-1
so it's decelerating but this answer is wrong where did it go oh so wrong?
2. (Original post by Big white)
https://2802a3b1a650824d2586fd3336bd...%20Edexcel.pdf

question 7 part c

my diagram has a big 800kg square on the right and a stick in the middle connected to a 200 kg square
on the 800kg square , it has 400N and FN and tension of 100N in the towbar all going left
on the 200kg square it has 100N in the towbar and just 200N going to the left

calculating for the acceleration i used f=ma on the trailer(200kg square)
200-100=200a defining positive as left
thus a=0.5ms^-1
so it's decelerating but this answer is wrong where did it go oh so wrong?
let me draw you a diagram

Edit: here...

there is no tension in the car, its both thrust.
3. (Original post by KloppOClock)
let me draw you a diagram

Edit: here...

there is no tension in the car, its both thrust.
I didn't say there was any tension in the car i said it was in the towbar so this is how i've drawn my diagram
Attached Images

4. (Original post by Big white)
I didn't say there was any tension in the car i said it was in the towbar so this is how i've drawn my diagram
there is no tension, there is only thrust
5. (Original post by KloppOClock)
there is no tension, there is only thrust
but it's in the towbar??? so surely the diagram i've drawn is right?
6. When decelerating, the tension becomes thrust as the objects want to move closer together and the towbar prevents this by pushing outwards (not sure if this is the truth but it's how I think about it), thrust acts outwards from the center so your "T" arrows should be flipped.
7. (Original post by Big white)
but it's in the towbar??? so surely the diagram i've drawn is right?
The car is slowing down from high speed. As the tow bar cannot compress, there is thrust.

Thrust is basically the opposite of tension, you either have thrust or tension depending on the acceleration
8. (Original post by JN17)
When decelerating, the tension becomes thrust as the objects want to move closer together and the towbar prevents this by pushing outwards (not sure if this is the truth but it's how I think about it), thrust acts outwards from the center so your "T" arrows should be flipped.
ah... thanks so much! I've gotten it now
9. (Original post by KloppOClock)
The car is slowing down from high speed. As the tow bar cannot compress, there is thrust.

Thrust is basically the opposite of tension, you either have thrust or tension depending on the acceleration
Thanks a lot i've got it now

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Updated: June 7, 2016
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