I just wanted some one to check over my answer because i am doing my hw online and it keeps telling that my answer is close, and that i have made a rounding error or used the wrong sig figs.(adsbygoogle = window.adsbygoogle || []).push({});

The problem is

A baseball is thrown from the roof of a building of height 22.1 m with an initial velocity of magnitude 12.1 m/s and directed at an angle of 53.1^{o}above the horizontal.

What is the speed of the ball just before it hits the ground.

Ok i split the problem into two parts. From the point he threw the ball to when it reaches its max height and then from its max height to the point where it hits the ground. For the first part its going to be

K_{i}+ U_{i}= K_{f}+ U_{f}

the intial potential energy is going to be zero.

I used this equation to find the max height it reached and i got 4.78m.

Then i used the equation again except this time it has to final potential energy. I used 26.9 as my height and solved for the final velocity. And i got 22.9m/s. But the thing keeps telling me i am close. I tried to find the answer using kinematics and i got the same answer. Can some one tell me if i am doing something wrong.

Thanks

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# Homework Help: Help with projetile motion using Energy Theorem

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