Presentation on theme: "MR. MCMARTIN BETA POD SCIENCE What is Force?. Interesting Fact Basic Forces of Nature Scientists have found evidence that the interactions of only four."— Presentation transcript:
MR. MCMARTIN BETA POD SCIENCE What is Force?
Interesting Fact Basic Forces of Nature Scientists have found evidence that the interactions of only four basic forces can describe all physical properties and relationships in nature. These forces are: The gravitational force, which acts on all matter (which has mass) and on light (which has no mass). The electromagnetic force, which is responsible for the attraction and repulsion of all kinds of matter that have electric or magnetic properties. The strong nuclear force, which binds the protons and neutrons of atoms together in the nucleus. The weak nuclear force, which describes some interactions between subatomic particles.
Force and Measurement Force: a push or a pull A force can change acceleration of an object. Acceleration can be change in speed or direction Anytime you see a change in motion of an object you can be sure it was created by a force. Force is expressed (or labeled) in units called Newtons. Newton: the SI unit for force.
True statements All forces act on objects. For any push to occur, something has to receive the push. The same is true for any pull. Just because force acts on an object doesn’t mean that motion will occur. Ex. You’re sitting on a chair, but your chair doesn’t move because the floor is pushing back up on the chair.
Unseen Sources and Receivers of Forces It’s not always easy to tell what is exerting a force or what is receiving a force. Ex. Magnets and Gravity
Determining Net Force Usually, more than one force is acting on an object. Net force: the combination of all forces acting on an object. To determine the net force you must first determine the direction of the forces. Forces in the same direction: add the forces Forces in opposite directions: subtract the smaller force from the larger force. The direction would then go towards the larger force.
Balanced and Unbalanced Forces If you know the net force on an object, you can determine the effect of the net force on the object’s motion. The net force tells you if the forces are balanced or unbalanced. Balanced force: When the forces on an object produce a net force of 0 N. Most forces around you are balanced. They need to be in order to stay in place. Ex. Walls around you. Unbalanced force: When the net force on an object is not 0 N. Produce change in motion Cause a non moving object to start moving Change in motion of a moving object which changes it’s direction and speed Objects can continue to move after unbalanced forces are removed. Ex. A pool ball continues to roll after being hit by the pool stick.