- #1
ScullyX51
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Homework Statement
A boy reaches out of a window and tosses a ball straight up with a speed of 10 m/s. The ball is 20 m above the ground as he releases it. Use energy to find:
1)The ball's maximum height above the ground.
2)The ball's speed as it passes the window on its way down.
3)The speed of impact on the ground.
Homework Equations
Etotal= PEi+KEi=PEf+KEf
Vf2-Vi2=2AD
KE=mv2
PE=mgy
hmax= v2/ 2g
The Attempt at a Solution
I solved for the first part and got it right by using the formula for hmax and got 5.1 ,and then added 20 m and got 25.1 meters which is correct.
For the second part I used vf2-vi2=2ad
and I got 10 m which is also correct.
I am having trouble finding the third one; I tried applying vf2 -vi2=2ad using 20 m and 25.1 m and both of them didn't work.
any suggestions.