Welcome to Chafia physic. In this post i just want to share with you about, What is terminal velocity and how it reached. Fisrt lets start about what is definition of teminal velocity.
Terminal velocity is a maximum velocity that a thing (example: a ball) can reached when it moves inside a fluid (example: air, water, oil, etc). The reason why this maximum velocity comes up is a force that called Drag Force, where it force has opposite direction with the movement. This opposite force in one situation will make the total force to be zero, and make the ball moves in constant velocity.
To get more understanding with this situation let's we take a look with example below.
Problem:
A ball with mass m=0.01 kg and radius R=0.05m falling from the rooftop 120 m from street without initial velocity. If the density of Air is 1.2 kg/m^3 and the Drag coefficient is 0.5 (for sphere) Find terminal velocity of this ball. And compare with the velocity of ball before hit the street if the drag force neglect.
Answer:
To solve compared problem, first let's start to analyze a ball in free fall situation (without drag force)
From the calculation we get the magnitude of velocity when drag force is neglect is v = 48.49 m/s.
Now let's to analyze the force acting on the ball when Drag Force include. Look at the green ball.
In this case W is the weight of ball and Fd is dragforce. At the first falling situation W>Fd and it make a (acceleration) will have negative sign, that shows the ball is moving downward. At increased of time the ball velocity will rise up and this velocity will make Fd magnitude close to W. At one situation Fd will have same magnitude with W. So the total force will become zero.
As we know when the total force is zero there is no acceleration on the ball, in the other means ball moves with constant velocity. This is how terminal velocity can be reached.
Just want to remaind you Aeff is different with A of ball surface. Aeff is effective cross-sectional area, where this area is a prependicular area with ball that fluid flows. Ok after we get vt (terminal velocity equation) lets subtitute the constant that we know from the problem.
From calculation we get terminal velocity magnitude is 6.45 m/s.
If we compared this terminal velocity with free fall velocity we get before, we can see how air drag force can make huge different. Without air this very dangerous to drop something even this a very sall ball.
Ok i think that's all for this post. Thank you for all of you that visit this blog. See you later on another post. Keep Healty and rememmber dont drop anything in noDrag force situation.
writer : Muhammad raditiya
Refrence : Chafias.com/Apa yang dimaksud kecepatan terminal
NASA/ Terminal Velocity
Terminal velocity is a maximum velocity that a thing (example: a ball) can reached when it moves inside a fluid (example: air, water, oil, etc). The reason why this maximum velocity comes up is a force that called Drag Force, where it force has opposite direction with the movement. This opposite force in one situation will make the total force to be zero, and make the ball moves in constant velocity.
To get more understanding with this situation let's we take a look with example below.
Problem:
A ball with mass m=0.01 kg and radius R=0.05m falling from the rooftop 120 m from street without initial velocity. If the density of Air is 1.2 kg/m^3 and the Drag coefficient is 0.5 (for sphere) Find terminal velocity of this ball. And compare with the velocity of ball before hit the street if the drag force neglect.
Answer:
To solve compared problem, first let's start to analyze a ball in free fall situation (without drag force)
Now let's to analyze the force acting on the ball when Drag Force include. Look at the green ball.
If we compared this terminal velocity with free fall velocity we get before, we can see how air drag force can make huge different. Without air this very dangerous to drop something even this a very sall ball.
Ok i think that's all for this post. Thank you for all of you that visit this blog. See you later on another post. Keep Healty and rememmber dont drop anything in noDrag force situation.
writer : Muhammad raditiya
Refrence : Chafias.com/Apa yang dimaksud kecepatan terminal
NASA/ Terminal Velocity
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