A feather floating through the air has more kinetic energy because the rock is not in motion its on the ground the feather is moving in the air at a pretty fast rate of speed.
An electronic cardiac monitor is the preferred method for assessing heart rate during chest compressions. While a person is performing chest compressions on a patient, he or she is hooked up to the electronic cardiac monitor so that the doctor can see exactly how fast the patient's heart is pumping blood. Cardiac monitoring is the best method do assess this.
