What is the speed of the 100g ball in Newton's Cradle after being lifted 3.0cm?

[madeeeeee]

Homework Statement

In David and Mervin's Newton's Cradle the 100 g ball was lifted a height of 3.0 cm. With what speed would it collide with the other balls at the bottom of its motion?

Homework Equations

Eg=mgh
Ek=1/2mv^2
100g=0.1 kg
3.0cm=0.03m


3. The Attempt at a Solution [/b]
Eg=mgh
Eg=(0.1kg)(9.8m/s^2)(0.03m)
Eg=0.0294J
Ek=1/2mv^2
0.0294J=1/2(0.1kg)(v)^2

Am i on the right track? I think i am doing something wrong

 

[diazona]

What do you think you're doing wrong? Or why do you think something is wrong?

 

[madeeeeee]

ok so what if i use the conservation of energy equation
Et=Ek=Eg

would the final equation be
mgh = 1/2mv2^2