How Do You Calculate the Force Between Children on Ice?

[AliciaNoogles]

Homework Statement

Three small children of mass, 20kg (first child),24kg(middle child) and 16kg (third child), respectively, hold hands and are pulled across a smooth frozen pond (which will occur sooner rather than later) by a larger boy on skates. He pulls thm via horizontal rope being held by the first child (20kg). The skater pulls on the rope with a force of 135N. Calculate each of the following :
-the acceleration of the skater
-the force with which each pair of children must hold hands to ensure that the chain is not broken.

Homework Equations

Fnet=ma

The Attempt at a Solution

I've solved the first part, which was 2.25, but for some reason i can't seem to get the right answer for the second part (90.0N, 36.0N). I've tried using Fnet=ma for the second part aswell, and haven't thought up anything else. I'm studying for a test, which is why I need to figure out how to do this, any help would be very much appreciated!

Never mind! i figured it out!

 

[Villyer]

What numbers are you using in the F=ma formula?

 

[AliciaNoogles]

I was adding the 20 and 24 and then multiplying by acceleration. I understand what I was doing wrong now, regardless, thank you for answering so fast!

 

[Villyer]

I'm glad you found the right answer.

You came to the conclusion that you add the 24 and 16 together instead, because those are the masses being accelerated, right?

 

[AliciaNoogles]

yes I did. Took me longer than I'm proud of though haha. Thanks