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Description
Flashcards by Jade Dickey, updated more than 1 year ago
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Created by Jade Dickey
over 8 years ago
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| Question | Answer |
| The Nature of Force | A force gives energy to an object, sometimes causing it to start moving, stop moving, or change direction. • A force can be a push or pull. • Newton: the unit used to express force (I pushed the chair with 50 N of force) • Net Force: the combination of all forces acting on an object |
| Forces Acting in the Same Direction | • When multiple forces act upon an object in the same direction, you ADD the forces to find the net force acting on the object. |
| Forces Acting in Opposite Directions | • When multiple forces act upon an object in the opposite directions, you SUBTRACT the forces to find the net force acting on the object. |
| Balanced Forces | Balanced forces cause NO CHANGE in motion • Forces that are in opposite directions and equal in size are called balanced forces. • When forces are balanced, there is no change in motion; there would be no overall force (net force) acting on the object. |
| Unbalanced Forces Same Direction | Unbalanced forces cause a CHANGE in motion Same direction - When two forces are acting in the same direction, they are added together. The size of the arrow is relative to the strength of the force. They each provide an “applied force” in the same direction. Meanwhile, gravitational force and frictional forces are working against them. |
| Unbalanced Forces-Opposite directions | • When two forces act in opposite directions, they combine by subtraction, • If one force is greater than the other force, the object will move in the direction of the greater force |
| Contact forces | are types of forces in which the two interacting objects are physically contacting each other. |
| Action-at-a-distance forces | are types of forces in which the two interacting objects are not in physical contact with each other, yet are able to exert a push or pull despite a physical separation. |
| APPLIED FORCE | PUSH OR PULL |
|  FRICTIONAL FORCE | GOES AGAINST THE DIRECTION OF THE MOTION |
| TENSIONAL FORCE | WHEN THINGS ARE PULLING IN OPPOSITE DIRECTION |
| NORMAL FORCE | OPPOSES THE GROUND |
| AIR RESISTANCE FORCE | TYPE OF FRICTIONAL FORCE |
| Friction | There are 4 types of friction: static, sliding, rolling and fluid. |
| Friction Pt. 2 | Friction is a force that acts in a direction opposite to the motion of the moving object causing the moving object to slow down and finally stop. • Friction arises from the fact that objects and surfaces are not perfectly smooth. • The amount of friction between two surfaces depends on how hard the surfaces are forced together and on the materials of which the surfaces are made. |
| Sliding Friction | When solid objects slide over each other, they produce sliding friction. In order to move the object you must exert a force larger than the force of friction. • The amount of sliding friction depends on: • weight of the moving object. • type of surface that the object is sliding across. |
| Rolling friction | • When an object rolls over a surface rolling friction is produced • Produced by objects such as wheels and ball bearings • it tends to be less than that of sliding friction. |
| Fluid Friction | • As an object moves through a fluid it produces fluid friction • All liquids and gases are fluids • Friction also exists when an object moves across or through a fluid. • Substance called lubricants (oil, wax, and grease), change sliding friction to fluid friction, thus reducing friction.  fluid friction is less than sliding friction. Air resistance is an example of fluid friction caused by the particles that make up air. |
| STATIC FRICTION | • When a force is applied to an object but does not cause it to move. • The force of static friction balances the applied force. • Static friction disappears as soon as an object begins to move |
|  Friction: Is it helpful or harmful? | • An example: • In your car friction can be both helpful and harmful, here is how: • When you press on the breaks you cause friction between them which HELPS slow down your car • In this same car there is friction between the moving parts in the engine. This friction causes the parts to wear out over time and therefore they must be replaced. • Friction between your foot and shoe can make holes in your socks! • Friction between your shoe and the floor helps you to stand upright. |
| WHY DOES AN APPLE FALL TOWARDS THE GROUND WHEN DROPPED? | • Isaac Newton asked this question in 1665. • The answer to this question gave birth to a law... THE LAW OF UNIVERSAL GRAVITATION • All objects in the universe attract each other through gravitational force. • The size of this force depends on the masses of the objects and the distance between them. • So... • Gravitational force increases as mass increases. • Gravitational force decreases as distance increases. |
| How Mass Affects Gravitational Force (Photo) | |
| How Distance Affects Gravitational Force (Photo) | |
| Gravity | On Earth, all objects experience a "downward" force of gravity. • The force of gravity on an object is always equal to the weight of the object. • Gravity is of great importance in the interaction of all objects in the universe; • it binds us to the Earth, • holds the Earth and all planets in the solar system, |
| Free Fall (Photo) | |
| Terminal Velocity (Photo) | |
| Weight | • a measure of the force of gravity on an object • Metric or SI unit is the Newton (N) according to the force of gravity pulling on you •The force of gravity varies according to the distance the object is from the center of the Earth. - You weigh less on top of a mountain than you do at sea level. •Your weight varies |
| GRAVITY IN MOTION | • All objects fall to the ground at the same RATE because the acceleration due to gravity is the same for all objects. • This is because heavier objects experience more gravitational pull but are also harder to accelerate than a lighter object. |
| A FEW MORE THINGS ON ACCELERATION DUE TO GRAVITY | • All objects fall to the ground at the same rate; HOWEVER, differences in the size, shape and speed of an object can increase or decrease air resistance. • As speed increases so does air resistance • At a certain point the two will equal out and the object will fall at its terminal velocity (a constant rate). |
| Projectile Motion | |
|  Orbital Motion |
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