Levon throws a ball straight upwards with an initial velocity of 15.0 m/s.

Question

a.How high will it reach?
b.How long will it take unit his friend in a tree 5.0 m above him catches the ball? (he catches the ball on its way back down)

Answer 1

a. V^2 = Vo^2 + 2g*h = 0
h = -Vo^2/2g = -225/-19.6 = 11.5 m.

b. V = Vo + g*Tr = 0.
Tr = -Vo/g = -15/-9.8 = 1.53 s. = Rise
time.

0.5g*Tf^2 = 11.5-5 = 6.5 m.
4.9Tf^2 = 6.5
Tf^2 = 1.33
Tf = 1.15 s. = Fall time.

Tr+Tf = 1.53 + 1.15 = 2.68 s. To catch
the ball.