• December 16th, 2010, 07:20 PM
mjr150
You have a straw. This straw is fixed on one end on a pivot and on the other end, it can travel from left to right. Compare this to the minute hand on a clock that can travel from 9:00AM to 3:00PM.

I’m using a straw in this example because it can contain a projectile. That’s what I love about this forum. You can ask questions that have physical and technological limitations and yet everyone understands what your real question is.

Anyway, my question is about maximum velocity of two scenarios. I’ll use A for one and B for the other for the question. It’s not important that B be greater than A, or A be greater than B, but rather, I want to know if they are equal.

Scenario A: A projectile is inserted near the middle “clock” of the straw. The hand moves at a high velocity from 9:00AM to 3:00PM where the projectile reaches the end of the opposite side of the straw at 3:00PM and exist the straw.

Scenario B: A projectile is inserted at the end of the straw “You can see is sitting on 9:00AM”. The straw moves from left to right at the same velocity at scenario A. At 3:00PM, the projectile is released.

Are they released at the same speed?
• December 16th, 2010, 08:37 PM
Harold14370
In scenario B the projectile has a velocity when released equal to the velocity of the end of the barrel and in a direction tangent to the circle that the end of the barrel is describing. In scenario A, the projectile has the same tangential speed as B, plus a radial velocity at a right angle to the tangential velocity. So, I'd say that the projectile in Scenario A is moving faster.
• December 16th, 2010, 09:01 PM
mjr150
My mind tells me that isn't possible for B to travel faster than A. My mind also tells me that it's possible for A to travel faster than B.

The reason why I'm curious is because of the application. In the real world, A is far more complex.

So much so that for A has to be significantly faster than B for A to be used. In other words, A > B for is required for A to be used and A = B doesn't nearly cut it.