Hi. I am currently working on a problem involving a ball being dropped from a hieght of 4m making a perfectly elastic collision with the ground. Assuming no mechanical energy is lost due to air resistance, I must find the period of the motion. I used the equation V(final) = V(initial) - gt where V(initial)=0 therefore V(final)= -9.8t and V^2(final) = V^2(initial) - 2gh h= -4m V(final)= -9.8t so i replaced these values in the equation, and i find t= 0.9035 seconds To find T, I simply multiplied 0.9035 sec by 2. However, my answer does not correspond that what it says in the book, and now i'm lost! Can someone help me by telling me if my method is right or wrong? I would really appreciate it!! Thank you!