Finding Initial Velocity of a Ball Using Time and Distance

AI Thread Summary
To find the initial velocity of a ball thrown upward, the total flight time is calculated as 2.1 seconds, combining the time it takes to pass a window on the way up and down. The upward and downward motions are symmetrical, meaning the time to reach maximum height is half of the total flight time, which is 1.05 seconds. At maximum height, the ball's velocity is zero, allowing for calculations of distance and final velocity using the time taken to fall back down. By applying kinematic equations, the initial velocity can be determined. This approach effectively uses time and distance to solve the problem.
thegreatone09
A ball is thrown up into the air and it passes a certain window 0.3s after being released. It passes the same window on its way back down 1.50s later. What was the intial velocity of the ball?
Any help will be appreciated.
 
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Ask yourself what the total flight time of the ball was.
 
Here's a simple hint I can give: if resistance is ignored, then the upward motion is 'symmetrical' to the downward motion.
 
total time

If you haven't got it by now the total time is 0.3 +1.5 + 0.3 = 2.1 s. Since the velocity is zero at it's maximum height you can divide the time in half to find how long it takes the ball to fall from its maximum height to the ground. Then use that time to calculate distance and then final velocity.
 

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