Max speed of a mass on a spring given x=0

[khairurraziq]

Homework Statement

determin the maximum speed attained by a mass when it is released from the x=0 position

Homework Equations

E=(kx)/2
E=mgh
E=1/2mv^2

The Attempt at a Solution

so i assumed that when the mass is at max speed the net force is 0. so
force of gravity=force of spring
mg=-kx
since both forces are equal then both energies must be equal as will
mgh=(kx^2)/2
so one of these times 2 plus the kinetic energy must be equal to the total energy.
but
what is the total energy.
it would be something like:
mass*gravity*total extension


i have no idea where to go from here. am i on the right track?

 

[tiny-tim]

welcome to pf!

hi khairurraziq! welcome to pf!

(try using the X² icon just above the Reply box )

so i assumed that when the mass is at max speed the net force is 0. so
force of gravity=force of spring
mg=-kx

yes, that's correct

since both forces are equal then both energies must be equal as well

no …

use conservation of energy: PE_gravity + PE_spring + KE = constant

 

[khairurraziq]

thanks,
ya i figured it out right after i posted this. it was so simple i want to slap meself!