Newton's Laws of Motion
by: Meaghan McInnis
Newton's Law of Inertia
Newton's law of inertia, or Newton's second law of motion, states that an object will not change speed or direction unless acted on by an unbalanced force. Inertia is the tendency of an object to resist a change in motion. An object at rest will stay at rest unless acted on by and unbalanced force. An object in motion will stay in motion at the same speed and direction unless acted on by an unbalanced force.
Newton's law of inertia says that an object at rest will stay at rest until acted on by an unbalanced force. In the picture above all of the forces are balanced so the benches will continue to move at the same speed in the same direction until an unbalanced force comes along. Since the objects are at rest, they will continue to stay at rest until there is an unbalanced force that interferes.
In the above picture everything is staying still. an object at rest will stay at rest until acted on by an unbalanced force. All of the forces in the picture are balanced. Nothing will move unless there is an unbalanced force involved because Newton's law of inertia says so.
Newton's Law of Force and Acceleration
Newton's law of force and acceleration, or Newton's second law of motion, states that the acceleration of an object depends on the mass of the object and the force applied. Acceleration is the rate at which velocity changes over time. Acceleration happens when an object changes speed, direction, or both. Acceleration can be found by using the formula a=F/m. Acceleration is speeding up, slowing down, starting, stopping, or changing direction.
The objects in the picture are stationary. This is because the net force being exerted on them is equal to 0N. Acceleration depends on the net force and the mass of the object. So Newton's law of acceleration applies to this photo.
The comet in the picture above is in motion. Its acceleration depends on its mass and the net force applied. This is how Newton's law of acceleration applies to this example.
Newton's Law of Action/Reaction
Newton's law of action/reaction, or Newton's third law of motion, states that for every action the is an equal and opposite reaction. This law basically means that all forces act in pairs. Every action force causes a reaction that is both equal in size and strength.
The girl that is jumping in the picture is going up even though the force she exerted was directed downwards at the ground. For every action there is an equal and opposite reaction. The action is the girl pushing on the ground. the reaction is the girl going upwards. The reaction is equal in both size and strength.
In the image to the right the cat is pushing on the glass. This is the action. When the cat pushes on the glass it will cause an equal and opposite reaction and the glass will fall to the floor. The reaction is equal in size and strength.