Conservation of Mechanical Energy

Check if friction is neglected, write total mechanical energy, calculate known PE or KE, and use total = KE + PE to find the missing value.

A three-position fall diagram can show maximum PE at top, mixed PE and KE in between, and maximum KE near bottom.

Saying total mechanical energy increases during falling is wrong because gravity converts PE into KE without creating extra mechanical energy when losses are ignored.

Conservation of mechanical energy means that the sum of kinetic energy and potential energy remains constant when only conservative forces like gravity act and friction is neglected.

Conservation of mechanical energy means that the sum of kinetic energy and potential energy remains constant when only conservative forces like gravity act and friction is neglected. Mechanical energy = KE + PE. If friction is absent, KE_initial + PE_initial = KE_final + PE_final. A freely falling ball loses gravitational potential energy and gains kinetic energy as it comes down.

Mechanical energy is KE + PE. During free fall without air resistance, potential energy decreases while kinetic energy increases by the same amount. The total mechanical energy remains unchanged. With friction, some mechanical energy changes into heat and sound, so mechanical energy alone is not conserved. Mechanical energy = KE + PE. If friction is absent, KE_initial + PE_initial = KE_final + PE_final. A ball has 100 J PE at the top and starts from rest. If 40 J PE is left at some lower point, KE there is 60 J, ignoring air resistance. Questions ask energy distribution at different heights, conversion between KE and PE, or whether conservation applies with friction. Saying total mechanical energy increases during falling is wrong because gravity converts PE into KE without creating extra mechanical energy when losses are ignored.