Physics Question

[Aaron]

Hi Everyone,

Is there anyone that could help someone with this question? Any help would be appreciated!

"I have a question a science problem I saw on the first exam. Nothing complicated,it's the trajectory of a basketball...yes, the trajectory of a basketball! When is the slowest velocity of a basketball? I always though it would be like that of an artillery round or ICBM--the apogee (sp?) Or..would it be at it's slowest velocity the moment you release the shot?"

Thanks!

[Armagdn03]

Upon release (assuming an angle is present, say 45 degrees) it will have both forward (x plane) velocity, and upward (y plane) velocity. Their combined velocity is found using vector addition to find the hypotenuse, or the resultant vector. At the top of the arc, y plane velocity is reduced to zero, and only the x plane velocity remains. Then the ball begins to drop gaining an increase in y plane velocity once again. Thus the slowest point should be at the peak of the arc, where we are only considering its movement forward, and the y plane velocity is zero.

Or....

After the ball bounces and comes to rest, that point is pretty slow too.

[Iotayodi]

Or..would it be at it's slowest velocity the moment you release the shot?"

I agree with Armagdn03. Once the ball leaves the fingers at a certain velocity then the apogee would be the slowest. If you just dropped the ball the slowest would be at release.
Heres a good one. If you "shoot" an object faster than 9.8 metres per second per second from a plane straight down, disregarding air impedance,would the object maintain its original speed?

[Armagdn03]

9.8 m/s^2 is an acceleration, not a top speed. The top speed or "terminal velocity" is where the acceleration due to gravity equalizes with the loss due to air resistance. If you ignore air resistance, there will be no equalization and the object will continue to accelerate, in such an instance, the slowest speed would be upon release.

[sucahyo]

I think the ball will start decelerating once it released from throwing hand by air resistance. The slowest horisontal speed would be at hit point. Since the ball move in 3D, there is vertical speed too, it's vertical speed would change according to gravity acceleration. If it never go up the slowest vertical speed is when it just released. If it go up then the slowest vertical speed is at the apex. Wind can accelerate or decelerate it too up to certain speed.

Basically, the slowest speed can be anywhere depend on circumtances. Not enough data. Usually there is a mention of air drag, distance, angle, gravity contant, etc. Trajectory usually considered perfect parabolic. Don't ask the detail though, already forget most of it.