Solving Free Falling Objects Problem

[steph35]

Homework Statement

A girl throws her set of keys to her friend upward who is in a window 3.90m above. the keys are caught later at 1.30s by the friends hand.

Homework Equations

a. With what initial velocity were the keys thrown?
b. What was the velocity of the keys just before they were caught?

The Attempt at a Solution

a. i tried finding change in x/change in t but got the wrong answer
b. i tried using a kinematic equation and solving for Vfinal but got the wrong answer...

 

[LowlyPion]

Homework Statement

A girl throws her set of keys to her friend upward who is in a window 3.90m above. the keys are caught later at 1.30s by the friends hand.

Homework Equations

a. With what initial velocity were the keys thrown?
b. What was the velocity of the keys just before they were caught?

The Attempt at a Solution

a. i tried finding change in x/change in t but got the wrong answer
b. i tried using a kinematic equation and solving for Vfinal but got the wrong answer...

Consider using the equation:

$$x = x_0 + v_0 t + (1/2) a t^2$$