What is this formula used for and how do you know when to cancel variables out? KE1 + PE1 + w = KE2 + PE2 ?
- Andrew SmithLv 73 months ago
It is simply that energy is conserved. All the original energy must exist after the action. "Cancel variables out" is not a valid mathematical process. You can perform any operation on both sides. Add a value, subtract a value, multiply by a value and so on. If any of these can make the problem simpler then that is what we mean by cancelling.
ie if we know that PE1 = PE2 then KE1 + PE1 +w= KE2 +PE1
subtract PE1 from BOTH sides ( "cancelling")
KE1+w = KE2 That has simplified the problem for this specific case.
- Anonymous3 months ago
mechanical energy conservation:
KE1 + PE1 + w = KE2 + PE2
1 = initial state
2 = final state
KE = kinetic energy
PE = potential energy
W = work
being (kinetic energy or work theorem):
kinetic energy variation = work
KE2 - KE1 = W
KE1 + PE1 + KE2 - KE1 = KE2 + PE2
PE1 = PE2