Newton’s First Law states. “The velocity of an object will remain constant unless a net force acts on it.” It is often call the Law of Inertia.
- If an object is moving, it will continue moving with a constant velocity (in a straight line and with a constant speed) unless a net force acts on it.
- If an object is at rest, it will stay at rest unless a net force acts on it.
- Inertia is the tendency of the motion of an object to remain constant in terms of both speed and direction.
- The amount of inertia that an object has is dependent on the object’s mass. The more mass an object has the more inertia it has.
- If an object has a large amount of inertia (due to a large mass)
- It will be hard to slow it down or speed it up of it is moving.
- It will be hard to make it start moving if it is at rest.
- It will be hard to make it change direction.
- Examples of the effects of inertia might include:
- Inertia causes a passenger in a car to continue to move forward even though the car stops. This is the reason that seat belts are so important for the safety of passengers.
- Inertia is the reason that it is impossible for vehicles to stop instantaneously.
- Inertia is the reason that it is harder to start pushing a wheelbarrow full of bricks than to start pushing an empty wheelbarrow. The filled wheelbarrow has more mass and therefore, more inertia.
- Inertia is also the reason that it is harder to stop a loaded truck going 55 miles per hour than to stop a car going 55 miles per hour. The truck has more mass resisting the change of its motion and therefore, more inertia.