Physics kinetic energy question!?
Hi can somebody answer this questions please. I don't just want the answer, i would also like to see the working out please.
If a football is kicked upwards, such that it has an initial velocity of 15 m/s, then calculate how high it would rise (delta h) into the air. (hint: first calculate its kinetic energy, and thus the maximum gain in potential energy, rearrage a formula to find h)
best answer gets 10 points.
Thanks george for the answer, but i don't get it. Is the question wrong, as we need the mass? i don't know how to solve it without the mass.
- GeorgeLv 41 decade agoFavorite Answer
As you do not know the mass of the football it's KE = (mass) * v^2 = Nv^2
where N is its mass in Newtons and v = the initial velocity
As the ball reaches its maximum height the KE = zero Nu^2 = 0
where u is its final velocity = 0
from the formula v^2 = u^2 + 2ah where
a = acceleration due to gravity
h = the height
then h = (v^2 - u^2) / a where u = zero
The mass of the ball does not enter into the formula