What is the Velocity of a Block Released from a Compressed Spring?

[PattyCake]

A 1.2 kg block is held against a spring of force constant 1.0 x 10^4 N/m, compressing it a distance of 0.15m. How fast is the block moving after it is released and the spring pushes it away?

 

[elegysix]

think about conservation of energy, and the potential energy stored in the spring before release

 

[PattyCake]

i know that k=1.0 x 10^4
x(final)=-0.15
x(initial)=0
work=1/2kx^2= -112.5

but i don't know how to find the velocity

i tried using v^2=k/m (x^2)
and received 13.69m/s

 

[elegysix]

Do you think that's wrong?
You solved for v. v is the velocity. well technically the speed here, but I'd assume that's what your teacher meant.

 

[dean barry]

Looks good, average force seems to satisfy.