Two dimensional motion - intitial velocity?

AI Thread Summary
To find the initial velocity of a projectile thrown horizontally, first determine the time the projectile is in the air by analyzing the vertical motion, using the equation d = v_i t + 0.5at^2. Since the ball is dropped from a height of 8.0 m with no initial vertical velocity, this allows for the calculation of time. Next, use the horizontal distance of 10.0 m and the time calculated to find the constant horizontal velocity, applying the formula d = v_horiz t. This two-part approach effectively separates the independent vertical and horizontal motions to solve for the initial velocity. Understanding these principles is crucial for solving two-dimensional motion problems.
erico004
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two dimensional motion - intitial velocity??

so i have the vertical distance, 8.0 m, and the horizantal distance, 10.0 m, how do i find the initial velocity of the projectile??
 
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I'm guessing this problem says that something was fired horizontally at an initial velocity v...blah blah, find v. Is that correct?
 
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no :[

a student threw a ball horizontally out of a window 8.0 m above the ground. it was caught at ground level by another student who was 10.0 m away. what was the initial velocity of the ball?

no masssss
 
Ok. This is not hard. You have to break the problem up into two parts.

First, you want to find the time that the ball is in the air. To do this you only consider the vertical motion (You can do this since vertical and horizontal motion are independent of each other). So, initially there was no vertical velocity. using d=v_{i}t + \frac{1}{2}at^{2} you can solve for the time.

Next, you consider the horizontal motion. Now we know the time and the horizontal distance. We also know that the horizontal velocity will stay constant. Now you can use d=v_{horiz}t and solve for the velocity.

Hope that helps.
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
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