Saved Bookmarks
| 1. |
Prove the energy remains coserved for a freely falling mass m. |
|
Answer» n :-PROVE the energy remains conserved for a freely falling mass m.______________________Formulas :Potential energy U = mghKinetic energy K = 1/2 mv²Total energy = K + UAt AU = mghK = 0 since v = 0Total energy = K + U = mgh + 0 = mghAt BU = m g HH = h - xU = mg ( h - x )K = 1/2 m v²By laws of motion:v² = 2 gh= > v²= 2 gxK = mgxK + U = mg( h - x ) + mgx = mgh - mgx + mgx = mghAt CK = 1/2 m v² = 1/2 m × 2 gh [ v² = 2 gh ] = mghU = 0 since h = 0Hence K + U = mgh + 0 = mghObservations :In all cases ,K + U = mghThere fore the total mechanical energy remains constant.This verifies the Law of Conservation of Energy.__________________________________________ |
|