- #1
KaseyK
- 8
- 0
Homework Statement
A certain volleyball player can jump to a vertical height of 85 cm while spiking the volleyball.
Homework Equations
(a) How long is the player in the air for?
(b) What is the player's vertical take-off speed?
The Attempt at a Solution
Firstly I converted 85 cm to m, which is 0.85m.
I then drew a free-body diagram to help me visualize what was happening with the player. Sorry I can't draw it on here.
I then used the kinematic equation:
d=v1(t) + 1/2(a)(t^2)
Because I assumed that the inital velocity was zero (because he hasn't jumped up yet) the equation was left with:
d=1/2(a)(t^2)
.85x2 = 1/2(9.81)t^2
t = 0.61 seconds
The answer should be 0.83 seconds. Where did I go wrong?
I haven't attempted 'b' because I need to figure 'a' out first.
Thanks in advance for your help.
Kasey