How long does it take for a ball to hit the ground from a table edge?

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The discussion revolves around calculating the time it takes for a ball to hit the ground after falling from a table edge, as well as its velocity at that point. The ball, moving at 2.0 m/s with a frictional force of 0.23 N, was initially thought to have a final velocity of 0.656 m/s when reaching the edge, but corrections led to a revised value of 0.65 m/s. The time to hit the ground was recalculated, with the final consensus being approximately 0.44 seconds. Additionally, the ball is expected to land about 0.286 meters away from the table. The discussion also touches on the initial vertical velocity being zero when calculating the time to fall.
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Homework Statement


The ball is moving at 2.0m/s just 40cm before it hits the table edge. If the ball has a mass of 51.3 grams and experiences a 0.23 N frictional force between it and the table, how fast will it be moving when it reaches the table's edge?

The table is 0.92m tall. How long will it take the ball to hit the ground?

Homework Equations



X=Xo+Vot+(0.5)at2
Y=Yo+Voyt+(0.5)at2
X=Xo+Voxt
FNET=ma
Fg=mg
Quadratic Formula

The Attempt at a Solution



I used FNET=ma to solve for the acceleration and got -4.48m/s2. Then I used X=Xo+Vot+(0.5)at2 and the quadratic formula to solve for t and got 0.3 sec. I then plugged this into V=Vo+at to get a velocity of 0.656m/s. Is this correct?

For the second question: I have that it will take 0.09 sec for the ball to hit the ground and it will land 0.1719 meters away from the table.
Does this seem correct?

Thanks in advance for any help.
 
Last edited:
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In the first part, if you use
vf^2 = vi^2 - 2*a*s, you get slightly different vf value.
In the second part, your t value is wrong. In that case the initial velocity in the vertical direction is zero.
 
So if I were to set up a variable list for how long it will take the ball to hit the ground would it look like the following?

Xo=0m
X=?
Vox=1.91m/s
t=?
Yo=0.92m
Y=0m
Voy=-9.8m/s
g=-9.8m/s2

Using these values I got 0.09 seconds. But that does not seem right...
 
Yo=0.92m
Y=0m
Voy=-9.8m/s This is not correct. It should be zero.
g=-9.8m/s2
 
So I have redone this problem making some corrections and have come up with these answers:

-When the ball reaches the table's edge it will be moving 0.65m/s.
-It will take the ball 0.44 seconds to hit the ground.
-The ball will land 0.286 meters away from the table?

Have I gotten this problem correct?

And if I were to graph my y-component velocity, would it be a constant 0m/s?

Thanks!
 
Last edited:
-It will take the ball 0.44 seconds to hit the ground.
Time t is 0.43 s.
 
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