L3 - kinetic energy and elastic potential energy

Question 1

rearrange Ek=1/2xmxv²
(kinetic energy=½ x mass x velocity²)

Answer 1

v=√2Ek/m
m=2Ek/v²

Question 2

rearrange Ee=½xkxe²
(elastic potential=½ x spring constant x extension²)

Answer 2

e=√2Ee/k
k=2Ee/e²

Question 3

what is extension?

Answer 3

when an object, such as a spring, is stretched, the increased length is called its extension.