Newtons 1st Law Of Motion
Newtons Law of Inertia An object in motion or in rest tends to stay in rest until an outside force is applied to it to change its state of motion. An objects resistance to a change in its state of motion is called inertia. Inertia is measured by an object?s mass (NOT WEIGHT): Example: Which has more inertia a 3250 lb Elephant or a 2500 lb car moving at 25 mph? Answer: the elephant. The elephant has more mass which means that it has more inertia. It takes more force to change the elephants state of motion (make it move) than it does to stop the car because the elephant has more mass.