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31 Cards in this Set
- Front
- Back
What are the two types of values in physics?
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scalars and vectors
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Explain scalars
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In most basic math, simple numerical values are calculated, for instance 1 + 1 = 2, these simple numbers are known as scalar values, meaning they have magnitude but no direction. Mass is an example of a scalar value.
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Explain a vector:
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Value with magnitude and direction. A vector can tell you how large a value is and if it acts upward, left, right ,etc.
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___________ is a scalar value that tells you how fast an object is moving.
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Speed
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___________ tells you the direction and speed than an object is traveling.
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Velocity
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Describe force
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A push or pull that can result in an object's motion or change of shape, and has magnitude and direction, making it a Vector.
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What is force measured in?
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Newtons (N) in the metric system, Pounds Force (lbf) in standard system.
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Force can be noticed but no seen; what can it be considered as?
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interaction between two bodies
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Newton's Laws of Motion are the foundation of the field of _____________.
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Mechanics
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Newton's First Law of Motion (Law of Inertia)
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An object at rest remains at rest and an object in motion will remain in motion until a force is applied. (Soccer ball stays at rest until kicked, eventually stops because of forces [drag, friction] acted upon it)
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Newton's Second Law of Motion
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Acceleration of the object will be proportional to the sum of the forces being applied. Algebraically, Newton's second law is written: F = m * a F = Force m = Mass; kilograms (kg) or pound mass (lbm) a = Acceleration; meters/second squared (m/s2) or feet/second squared (ft/s2) |
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______________ is defined as the rate of change of an object's velocity.
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Acceleration Notes: Acceleration does not have to result in speed; it can also cause a change in direction, as is the case in centripetal, or rotational, acceleration. |
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Newton's third Law of Motion
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For every action there is an equal and opposite reaction. |
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Give a Static example of Newton's Third Law
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Leaning against a wall you apply a force on the wall and the wall applies a force on you. These two forces are the same magnitude but in opposite directions.
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Give a Dynamic example of Newton's Third Law
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Cars crashing. One car collides into a stationary car, both cars feel the same amount of force.
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Centripetal Force:
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The force that makes an object travel along a curved path. Centripetal force creates centripetal acceleration toward the center of a curved path.
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Centrifugal force:
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The reaction force of centripetal force that pulls an object toward the outside of the curved path. The results of centrifugal force is centrifugal acceleration.
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Give an example of Centripetal and Centrifugal force.
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When a ball on a string is swung in a circle, the string exerts a centripetal force on the ball, preventing it from leaving the circular path, and the resulting centrifugal force pulls the ball outward, causing tension in the string keeping it taut.
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Law of Universal Gravitation
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States that the Gravitational Force two bodies exert on each other is proportional to their masses and inversely proportional to the square of the distance between them.
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Explain Fg = m * g; Universal Gravitation Equation
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m = mass; kg or lbm g = acceleration due to gravity; 9.81 m/s2 or 32.2 ft/s2 |
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_____________ is merely a measure of the force of gravity of an object. (m * g)
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Weight; N or lbf
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Explanation of weight as a force:
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Means that an object, such as a book, resting on a table, exerts a force on the table; the table exerts a force of the same magnitude (weight of the object), back on the object.
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This force exerted back on the object opposing the object's weight is known as _____________.
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Normal force. Notes: "normal" because it is normal, or perpendicular to the table. If holding the book in your hands, you must apply an upward force to keep he book stationary; therefore you are supplying the normal force equal to the book's weight. |
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Center of Gravity or Center of Mass
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Essentially the average location of the object and is often used in physics to simplify problems, treating the object as a single particle with all of its mass at its center of gravity.
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Torque:
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or moment due to force, equals the distance of the force from the fulcrum, or pivot point, multiplied by the tangential force: T = F * r F = force r = torque arm or distance from the fulcrum Measured in Newton-meters (Nm) or foot-pounds-force (lbf-ft) |
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The normal force created by gravity also gives rise to a resistance to sliding known as _________.
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Friction |
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What are the two types of friction
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Static and Kinetic
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Static friction
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is the force of friction between two objects that are not moving relative to each other. (trying to push a refrigerator across a floor; static friction keeps it in place)
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The force necessary to start sliding an object is called __________.
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Striction
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Kinetic friction
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Once you over come the striction point of an object, Kinect friction will apply a constant opposition no matter how hard or fast force is applied.
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