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a 17th century scientist, put forth a variety of laws that explain the interaction of forces and objects and the way in which the motion of an object is affected by force.: 

a 17th century scientist, put forth a variety of laws that explain the interaction of forces and objects and the way in which the motion of an object is affected by force. Newton's Three Laws of Motion. I saac Newton , These three laws have become known as

This video presentation will be all about Newton’s First Law of Motion or sometimes referred to as : 

This video presentation will be all about Newton’s First Law of Motion or sometimes referred to as Law of INERTIA. stated as: “An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.”

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Once standing still, it will stay still. The first law also means that if an object is standing still and is not contacted by any force, it will continue to remain motionless. Actually, a motionless object is just a special case of an object that is maintaining constant velocity. Its velocity is constantly 0 m/s. In the scene above we see an object (purple ball) that is standing still. On its own it will continue to stand still as long as we do not influence it with a force, that is, with an unbalanced, non-zero force.

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Let us now hear some thoughts from Professor Mac.

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In the video I illustrate the law by conducting an experiment.  I use a block of wood as the object and a frictionless surface, a surface that provides no resistance to the block moving on it.  In the real world all surfaces have some friction.  However in my virtual laboratory I can create ideal surfaces which have no resistance. What this means is that if an object is not moving then we can conclude that all the forces on the object are in balance.  If they weren’t in balance then the object would accelerate under the action of the unbalanced forces. Since the block is not moving, Newton’s first law tells us that the forces- gravity (acting down) and normal force (acting up) on the block must be in balance, otherwise it would start moving. “An object will remain in its state of rest unless acted upon by an unbalanced force.”

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Once moving at a steady speed in a straight line, it will continue moving at a steady speed in a straight line. The first law says that if an object is not pushed or pulled upon, its velocity will naturally remain constant. This means that if an object is moving along, untouched by a force of any kind, it will continue to move along in a perfectly straight line at a constant speed.

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In the animation we see an object (blue box) that is already moving along when we encounter it. As long as we do not push or pull it, as long as it does not run into something else or rub against something else, it will continue to move in a straight line at constant speed. It will continue to do this on its own without the need for any influence from other agents.

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Let us now hear some thoughts from Professor Mac.

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So what if we introduce a horizontal force?  What do you think will happen? Well in the video I do this by using the piston next to the block.  The piston pushes the block to the right and the block changes from being stationary to moving horizontally. Newton’s first law tells us that this is because there is an unbalanced horizontal force acting on the block from the piston . What this means is that if an object is moving in a straight line and continues to do so without increasing or reducing velocity, then the forces on the object are in balance. If they weren’t in balance then the object would accelerate or decelerate under the action of the unbalanced forces. In the experiment, there are no horizontal forces on the block as there is no piston force and the highly polished surface provides no resistance to the motion of the block. The vertical forces are still the same and therefore still in balance. “An object will continue in its state of uniform motion (constant velocity) in a straight line unless acted upon by an unbalanced force.”

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So I raised the question of what would happen if the block was moving on a surface which provided resistance to the motion. This is the type of surface which we encounter during everyday life.  The resistance is caused by something we call friction. If the block was moving on a surface with friction there would be a resistive force to the motion as shown in the figure that will be shown. In this case the friction force will slow the object down until it comes to rest.  When the block comes to rest the friction force reduces to zero. You can represent this friction as a force arrow.  Looking at the forces you can see that the forces in the horizontal direction are now unbalanced.  You can therefore conclude that the motion of the object will change – remember that an unbalanced force will change the motion of the block.

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Understand that we are saying if no outside force is applied, the velocity of the object (which is its speed and direction) will remain constant. An object traveling in a straight line at constant speed has a constant velocity. An object standing still has a constant velocity too. Its constant velocity is zero in value. In order to change either of these examples of constant velocity, you need to apply a non-zero force to the object. Then, when the force is applied, the velocity will change, and the object experiences an acceleration.

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Now, what about if there is more than one force on the object? You really can push an object, say, to the left and down at the same time, so, what happens then? Under these conditions we must realize that a group of forces on an object adds up so that all the forces appear to the object as one force. This one force that is the sum of all the forces is called the net force. The word net in this context means total. It is this net force that may change the velocity of the object. Let us look at an example. Imagine that two forces act at the same time on an object. One is a very strong force to the left, and the other is a weaker force to the right. These two forces add up to one net force. Since the force to the left is stronger, the net force is to the left. This net force to the left will cause the velocity of the object to change. The object experiences this one net force as if this was the only force pushing it, although, actually, there are two separate forces present.

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The law of inertia is most commonly experienced when riding in cars and trucks. The Car and The Wall Consider for instance this unfortunate collision of a car with a wall. Upon contact with the wall, an unbalanced force acts upon the car to abruptly decelerate it to rest. Any passenger in the car will also be decelerated to rest IF they are strapped to the car by seat belts. Being strapped tightly to the car, the passenger share the same state of motion as the car. As the car accelerates, the passengers accelerate with it; as the car decelerates, the passengers decelerate with it; and as the car maintains a constant speed, the passengers maintain a constant speed as well. But what would happen if the passengers were not wearing the seat belt? What motion would the passengers undergo if they failed to use their seat belts and the car were brought to a sudden and abrupt halt by a collision with a wall? Were this scenario to occur, the passengers would no longer share the same state of motion as the car. The use of the seat belt assures that the forces necessary for accelerated and decelerated motion exist. Yet, if the seat belt is not used, the passengers are more likely to maintain its state of motion. If the car were to abruptly stop and the seat belts were not being worn, then the passengers in motion would continue in motion. Assuming a negligible amount of friction between the passengers and the seats, the passengers would likely be propelled from the car and be hurled into the air. Once they leave the car, the passengers becomes projectiles and continue in projectile-like motion. Now perhaps you will be convince of the need to wear your seat belt. Remember it's the law. The Law of Inertia.

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Newton's First Law of Motion, also called Law of Inertia states that an object in motion tends to stay in motion unless an external force acts upon it. Similarly, if the object is at rest, it will remain at rest unless an unbalanced force acts upon it. To sum it all up: Basically, what Newton’s first Law is saying is that objects behave predictably. Moving objects don’t change their direction unless a force causes them to move from their path. This project was submitted by: Jannin Constance C. Chatto Source: http://learnwithmac.com http://www.physicsclassroom.com/class/newtlaws/u2l1a.cfm http://zonalandeducation.com/mstm/physics/mechanics/forces/newton/newtonLaw1.html