Term
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Definition
| system of objects that are not moving with respect to one another |
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Term
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Definition
| movement in relation to a frame of reference |
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Term
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Definition
| length of a path between two points |
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Term
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Definition
| quantity that has magnitude and direction |
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Term
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Definition
| vector sum of two or more vectors |
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Definition
| is the direction from the starting point and the length of a straight line from the starting point to the end point |
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Term
| what is needed to describe motion accuratly and completely? |
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Definition
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Term
| how do you add displacements? |
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Definition
| add displacements using vector addition |
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Term
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Definition
| ratio of the distance an object moves to the amount of time the object moves |
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Term
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Definition
| the rate at which an object is moving at a given moment in time |
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Term
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Definition
| the total distance traveled divided by the time it takes to travel that distance |
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Term
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Definition
| the speed and direction in which an object is moving |
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Term
| how are instantaneous speed and average speed different? |
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Definition
| average speed is computed for the entire duration of a trip, and instantaneous speed is measured at a particular instant |
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Term
| how can you find the speed from a distance-time graph? |
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Definition
| the slope of a line on a distance-time graph is speed |
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Term
| how are speed and velocity different? |
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Definition
| velocity is the description of both speed and direction of motion. velocity is a vector |
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Term
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Definition
| two or more velocities add by vector addition |
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Term
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Definition
| rate at which velocity changes |
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Term
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Definition
| the movement of an object toward earth solely because of gravity |
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Term
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Definition
| steady change in velocity |
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Term
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Definition
| a graph in which the displayed data form a straight line |
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Term
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Definition
| a graph in which the displayed data form a curved line |
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Term
| how are changes in velocity described? |
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Definition
| acceleration can be described as changes in speed, changes in direction, or changes in both. Acceleration is a vector |
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Term
| how can you calculate acceleration? |
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Definition
| you calculate acceleration for straight-line motion by dividing the change in velocity by the total time |
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Term
| how does a speed-time graph indicate acceleration? |
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Definition
| the slope of a speed-time graph is acceleration |
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Term
| what is instantaneous acceleration? |
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Definition
| instantaneous acceleration is how fast a velocity is changing at a specific instant |
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Term
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Definition
| push or pull that acts on an object |
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Term
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Definition
| force that causes 1-kilogram mass to accelerate at a rate of 1 meter per second each second |
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Term
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Definition
| overall force acting on an objectafter all the forces are combined |
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Term
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Definition
| force that opposes the motion of objects that touch as they move past each other |
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Term
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Definition
| friction force that acts on objects that are not moving |
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Term
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Definition
| force that opposes the direction of motion of an object as it slides over a surface |
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Term
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Definition
| friction force that acts on rolling objects |
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Term
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Definition
| opposes the motion of an object through a liquid |
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Term
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Definition
| fluid friction acting on an object moving through the eye |
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Term
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Definition
| is a force that acts between any two objects |
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Term
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Definition
| constant velocity of a falling object when the force of air resistance equals the force of gravity |
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Term
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Definition
| the motion of a falling object after it is given an initial forward velocity |
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Term
| how do forces affect the motion of an object? |
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Definition
| a force can cause a resting object to move, or it can accelerate a moving object by changing the object's speed or direction |
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Term
| what are the four main types of friction? |
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Definition
| there are four main types of friction: static friction, sliding friction, rolling friction, and fluid friction |
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Term
| how do gravity and air resistance affect a falling object? |
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Definition
| gravity causes objects to accelerate downward, whereas air resistance acts in the direction opposite to the motion and reduces acceleration |
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Term
| in what direction does earths gravity act? |
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Definition
earth's gravity acts downward toward the center of earth |
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Term
| why does a projectile follow a curved path? |
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Definition
| the combination of an initial forward velocity and the downward vertical force of gravity causes the ball to follow a curved path |
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Term
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Definition
| tendency of an object to resist a change in its motion |
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Term
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Definition
| measure of the inertia of an object and depends on the amount of matter the object contains |
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Term
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Definition
| force of gravity acting on an object |
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Term
| how does Newton's first law relate change in motion to a zero net force? |
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Definition
| according to newton's first law of motion, the state of motion of an object doesn't change as long as the net force acting on the object is zero. inertia |
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Term
| how does Newton's second law relate force, mass, and acceleration? |
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Definition
| according to newton's second law of motion, the acceleration of an object is equal to the net force acting on it divided by the object's mass |
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Term
| how are weight and mass related? |
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Definition
| mass is a measure of the inertia of an object; weight is a measure of the force of gravity acting on an object |
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Term
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Definition
| product of an object's mass and its velocity |
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Term
| law of conservation of momentum |
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Definition
| if no net force acts on a system, them the total momentum of the system does not change |
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Term
| what is newton's third law of motion? |
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Definition
| according to newton's third law of motion, whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object |
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Term
| what is needed for an object to have a large momentum? |
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Definition
| an object has a large momentum if the product of its mass and velocity is large |
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Term
| how is momentum conserved? |
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Definition
| in a closed system, the loss of momentum of one object equals the gain in momentum of another object- the momentum is conserved |
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Term
| what force can attract and repel? |
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Definition
| electric force and magnetic force are the only forces that can both attract and repel |
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Term
| what force holds the nucleus together? |
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Definition
| two forces, the strong nuclear force and the weak nuclear force, act within the nucleus to hold it together |
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Term
| what is newton's law of universal gravitation? |
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Definition
| newton's law of universal gravitation states that every object in the universe attracts every other object |
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Term
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Definition
| the result of a force distributed over an area |
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Term
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Definition
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Term
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Definition
| a substance that assumes the shape of its container |
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Term
| how is pressure calculated? |
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Definition
| divide the force by the area over which the force acts |
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Term
| how does water pressure change with depth? |
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Definition
| water pressure increases as depth increases. |
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Term
| how is pressure distributed at a given level in a fluid? |
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Definition
| the pressure in a fluid at any given depth is constant, and it is exerted equally in all directions |
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Term
| How does air pressure change with altitude? |
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Definition
| air pressure decreases as the altitude increases |
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Term
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Definition
| device that uses pressurized fluid acting on pistons of different sizes to change a force |
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Term
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Definition
| the pressure difference between the top and bottom of the wing creates an upward force |
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Term
| how does Pascal's principle describe the transmission of pressure through a fluid? |
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Definition
| a change in pressure at any point in the fluid is transmitted equally and unchanged in all directions throughout the fluid |
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Term
| how does a hydraulic system work? |
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Definition
| an increased output force is produced because a constant fluid pressure is exerted on the larger area of the output piston |
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Term
| how does the speed of a fluid related to the pressure within the fluid? |
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Definition
| according to Bernoulli's principle, as the speed of a fluid increases, the pressure within the fluid decreases |
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Term
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Definition
| abitlity of a fluid to exert an upward force on an object placed in it |
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Term
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Definition
| upward force that acts in the opposite direction of gravity |
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Term
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Definition
| the buoyant force on an object is equal to the weight of the fluid displaced by the object |
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Term
| what is the effect of buoyancy on the apparent weight of an object? |
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Definition
| Buoyancy results in the apparent loss of weight of an object in a fluid |
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Term
| how can you determine if an object will float or sink in a fluid? |
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Definition
| if an object is less dense than the fluid it is in, it will float. If te object is more dense than the fluid is, it will sink |
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Term
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Definition
| product of force and distance |
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
| when does a force do work? |
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Definition
| for a force to do work on an object, some of the force must act in the same direction as the object moves. If there is no movement, no work is done. |
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Term
| how are work and power related? |
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Definition
| any part of a force that does not act in the direction of motion does no work on an object |
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Term
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Definition
| device that changes a force |
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Term
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Definition
| force you exert on a machine |
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Term
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Definition
| the distance the input force acts through |
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Term
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Definition
| the work done by the input force acting through the input distance |
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Term
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Definition
| the force that is exerted by a machine |
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Term
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Definition
| the distance the output force is exerted |
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Term
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Definition
| output force multiplied by the output distance |
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Term
| how do machines make work easier? |
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Definition
| machines make work easier to do. They change the size of a force needed, the direction of a force, or the distance over which a force acts |
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Term
| how are work input and work output related for a machine? |
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Definition
| because of friction, the work done by a machine is always less than the work done on the machine |
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Term
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Definition
| the mechanical advantage of a machine is the number of times that the machine increases an input force |
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Term
| actual mechanical advantage |
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Definition
| the mechanical advantage determined by measuring the actual forces acting on a machine |
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Term
| ideal mechanical advantage |
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Definition
| ima of a machine is the mechanical advantage in the adsence of friction |
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Term
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Definition
| percentage of the work input that becomes work output |
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Term
| how does actual mechanical advantage of a machine compare to its ideal mechanical advantage? |
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Definition
| Because of friction, is always present, the actual mechanical advantage of a machine is always less than the ideal mechanical advantage |
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Term
| why is efficiency of a machine always less than 100%? |
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Definition
| because there is always some friction, the efficiency of any machine is always less than 100% |
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Term
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Definition
| a rigid bar that is free to move around a fixed point |
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Term
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Definition
| the fixed point the bar rotates around |
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Term
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Definition
| the input arm of a lever is the distance between the input force and the fulcrum |
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Term
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Definition
| is the distance between the output force and the fulcrum |
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Term
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Definition
| simple machine that consists of two disks or cylinders, each one with a different radius |
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Term
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Definition
| a slanted surface along which a force moves an object to a different elevation |
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Term
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Definition
| v-shaped object whose sides are two inclined planes sloped toward each other |
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Term
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Definition
| an inclined plane wrapped around a cylinder |
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Term
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Definition
| simple machine that consists of a rope that fits into a groove in a wheel |
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Term
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Definition
| combination of two or more simple machines that operate together |
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Term
| what are the six types of simple machines? |
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Definition
| lever, wheel and axle, inclined plane, wedge, screw, and pulley |
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Term
| what determines the mechanical advantage of the lever? |
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Definition
| to calculate the IMA of any lever, divide the input arm by the output arm |
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Term
| what determines the mechanical advantage of the wheel and axle? |
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Definition
| to calculate the IMA of the wheel and axle, divide the radius where the input force is exerted by the radius where the output force is exerted |
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Term
| what determines the mechanical advantage of the inclined plane? |
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Definition
| the IMA of an inclined plane is the distance along the inclined plane divided by its change in height |
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Term
| what determines the mechanical advantage of the wedge? |
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Definition
| a thin wedge of a given length has a greater IMA than a thick wedge of the same length |
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Term
| what determines the mechanical advantage of the screw? |
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Definition
| screws with threads closer together have a greater IMA |
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Term
| what determines the mechanical advantage of the pulley? |
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Definition
| the IMA of a pulley or pulley system is equal to the number of rope sections supporting the load being lifted |
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