Key points:
- Velocity includes both speed and direction.
- Acceleration occurs if either or both parts of velocity change.
- Acceleration requires a force.



Originally Posted By: paul

so there is no force that the mass can apply to the turn as the mass enters the turn.

because the mass is no longer accelerating as it enters the turn.

It is accelerating in the turn. And therefore it is applying a force to the pipe.

We know it's accelerating because its velocity is changing.

As you surely know, velocity includes speed and direction. If any part of the velocity changes then it's accelerating. Obviously direction is changing, therefore it's accelerating, therefore it's applying a force to the pipe.




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centripetal acceleration is constant acceleration btw.
because the mass is constantly accelerating towards the center.

"towards the center" only sounds like a constant direction because of English. Obviously the direction of the center keeps changing. So the direction of the acceleration is also changing.




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since the 100 kg mass does not loose any of its velocity as it travels through the turn then it hasnt given any of its momentum to the pipe.

Its velocity does change. So it does transfer momentum with the pipe.

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only in a new direction

Exactly! The change of means the velocity is changing. That's because direction is part of velocity.


Note: I use the word "obviously" to show that an idea can easily be seen from common sense. If you can't see it then you must be looking for the wrong thing. In other words, if it's not obvious to you, then you're probably overthinking it or misunderstanding me.