That's easy if you look at Bernoulli's equation, or if you think of it as conservation of energy. If the the velocity increases where is the energy coming from? If there was a change in height it would be from the potential. There is no change in height. So how bout pressure? Velocity increases pressure decreases. Also if you suck on a straw really hard what does the liquid do travels faster. Does the straw in that case explode? Or collapse. It collapses. This is due to the liquid inside losing pressure and the outside atmospheric pressure remaining constant. Draw a picture it will help with the above the above description. Any other questions post them to the blog... So we can share.
John-Fred Crane
On May 10, 2014, at 2:11 PM, "John DiNofrio" wrote:
Me and some of the guys were studying for physics, and we couldn't understand why pressure goes down in this question.
We checked, and it's b, but we can't find out why.
Another example that I remember from 7th grade was inflating a trash bag. If you held the bag away from you and blew a stream of air into it, the faster flowing air would create a vacuum, drawing in the surrounding air and inflating the bag very quickly. -Kevin Meglathery
A fluid flows steadily from left to right in the pipe shown above. The diameter of the pipe is less at point 2 than at point 1, and the fluid density is constant throughout the pipe. How do the velocity of flow and the pressure at points 1 and 2 compare?
Mr. Crane i haven't been in class in like 2.5 weeks but i checked power school and got 50's on two assignments that i'm not even sure if i did/handed in so i'm a little confused about my current grade.
That's easy if you look at Bernoulli's equation, or if you think of it as conservation of energy. If the the velocity increases where is the energy coming from? If there was a change in height it would be from the potential. There is no change in height. So how bout pressure? Velocity increases pressure decreases.
ReplyDeleteAlso if you suck on a straw really hard what does the liquid do travels faster.
Does the straw in that case explode? Or collapse.
It collapses. This is due to the liquid inside losing pressure and the outside atmospheric pressure remaining constant.
Draw a picture it will help with the above the above description. Any other questions post them to the blog... So we can share.
John-Fred Crane
On May 10, 2014, at 2:11 PM, "John DiNofrio" wrote:
Me and some of the guys were studying for physics, and we couldn't understand why pressure goes down in this question.
We checked, and it's b, but we can't find out why.
**
~ John DiNofrio
~ John DiNofrio
**
Another example that I remember from 7th grade was inflating a trash bag. If you held the bag away from you and blew a stream of air into it, the faster flowing air would create a vacuum, drawing in the surrounding air and inflating the bag very quickly.
Delete-Kevin Meglathery
Here is the question for that one:
DeleteA fluid flows steadily from left to right in the pipe shown above. The diameter of
the pipe is less at point 2 than at point 1, and the fluid density is constant throughout
the pipe. How do the velocity of flow and the pressure at points 1 and 2 compare?
Velocity Pressure
(a) v1 < v2 p1 = p2
(b) v1 < v2 p1 > p2
(c) v1 = v2 p1 < p2
(d) v1 > v2 p1 = p2
(e) v1 > v2 p1 > p2
Answer (b)
This comment has been removed by the author.
ReplyDeleteMr. Crane i haven't been in class in like 2.5 weeks but i checked power school and got 50's on two assignments that i'm not even sure if i did/handed in so i'm a little confused about my current grade.
ReplyDelete