 #1
simphys
 298
 43
 Homework Statement:

II) A vertical spring (ignore its mass), whose spring
constant is is attached to a table and is
compressed down by 0.160 m.
(a) What upward speed can
it give to a 0.380kg ball when released? (b) How high
above its original position (spring compressed) will the
ball fly?
 Relevant Equations:
 E1 = E2
for (a): I basically got the correct answer, but when resolved with taking different reference lines/frames I got a different answer.
for the 1st attempt I took y = 0 (for both ##U_{el}## and ##U_{grav}) at the position where the spring is uncompressed.
for the 2nd attempt (with wrong solution) I took y = 0 for ##U_{grav}## and x = 0 for ##U_{el}## as is shown on the following picture.
have I made a mistake or is this simply not possible?
if it is not clear, please tell me.
for the 1st attempt I took y = 0 (for both ##U_{el}## and ##U_{grav}) at the position where the spring is uncompressed.
for the 2nd attempt (with wrong solution) I took y = 0 for ##U_{grav}## and x = 0 for ##U_{el}## as is shown on the following picture.
have I made a mistake or is this simply not possible?
if it is not clear, please tell me.