How High Did the Basketball Player Jump?

[majormuss]

Homework Statement

A basketball player jumped straight up to grab a
rebound. If she was in the air for 0.80 second,
how high did she jump?
(1) 0.50 m (3) 1.2 m
(2) 0.78 m (4) 3.1 m

Homework Equations

d=Vit + 1/2at^2

The Attempt at a Solution

my calculations lead to '4' as my final answer, but the book tells me otherwise. There must be something I am missing. need help.

 

[rock.freak667]

Homework Equations

d=Vit + 1/2at^2

The Attempt at a Solution

my calculations lead to '4' as my final answer, but the book tells me otherwise. There must be something I am missing. need help.

The player is initially at rest and is only subjected to the acceleration of gravity.

 

[majormuss]

The player is initially at rest and is only subjected to the acceleration of gravity.

Exactly!, that's i also assumed and if u work it out with that formula the answer turns out 3.1 m/s... but the book says my answer should be 1.2m/s... doesn't make any sense to me at all.

 

[rock.freak667]

Exactly!, that's i also assumed and if u work it out with that formula the answer turns out 3.1 m/s... but the book says my answer should be 1.2m/s... doesn't make any sense to me at all.

Well actually '2' seems to work out more, I don't know how your book for 1.2m.

At the highest point, t=0.4s.

 

[Yitzach]

The problem is that the player's initial velocity is not zero, but unknown. I need to be on my way or I give the eq. you need.

 

[tiny-tim]

A basketball player jumped straight up to grab a
rebound. If she was in the air for 0.80 second,
how high did she jump?

Hi majormuss!

She reached the top after 0.40 seconds, so the question is the same as 'how far does something fall in 0.40 seconds?'

 

[majormuss]

Hi majormuss!

She reached the top after 0.40 seconds, so the question is the same as 'how far does something fall in 0.40 seconds?'

thanks bro, that was very helpful...it turns the answer was really '2', I misread!.. thanks everyone.