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41 Cards in this Set
- Front
- Back
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motion
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change in position of an object
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frame of reference
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the object or point from which movement is observed/determined
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distance
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how far an object moves
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displacement
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distance of an objects change in position from the starting point
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speed
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the distance an object travels in a given unit of time
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constant speed
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speed does not change
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average speed
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total distance divided by total time
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instant speed
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speed of any given point in time
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velocity
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includes speed and direction
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acceleration
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-the rate of change of the velocity of an object
-can be positive or negative (Vf-Vi) / t |
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friction
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the force that opposes motion between two surfaces that are touching each other
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Newton's 1st law of motion
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-law of inertia
-an object moving at a constant rate or at rest, remains that way until acted on by an unbalanced force |
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Newton's 2nd law of motion
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net force acting on an object causes the object to accelerate in the direction of the unbalanced force
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Newton's 3rd law of motion
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to every action force, there is an equal and opposite reaction force (equal in size and opposite in direction)
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gravitational force
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-formula for weight
-f=ma -acceleration due to gravity is 9.8m/s squared -all objects fall at the same rate in a vacuum |
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air resistance
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the force of air increases as speed increases
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terminal velocity
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the force of air resistance becomes the same as the force of gravity and the object does not fall any faster
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free fall
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objects seem to be weightless
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momentum
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-the force needed to change the motion of an object
-p=mv |
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law of conservation of momentum
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momentum is not created or destroyed; it just transfers between objects
p1 + p2 = p1 + p2 |
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projectile motion
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horizontal velocity is constant
vertical velocity is increasing due to gravity |
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law of conservation of energy
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energy cannot be created of destroyed; it only changes form
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work
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the transfer of energy that occurs when a forces makes an object move
w = fd |
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power
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the amount of work done in a certain period of time
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simple machine
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a machine that works w/ one movement
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types of simple machines
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-levers
--pulley --wheel and axle -inclined plane --wedge --screw |
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effort force
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force applied to a machine
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resistance force
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force applied by a machine to overcome resistance
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efficiency
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a measure of how much of the work put into a machine is changed into useful output work by the machine
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work in
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the work done ON a machine
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work output
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the work done BY a machine
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lever
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a bar that is free to pivot around a fixed point
IMA = Le x Lr |
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pulley
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fixed pulley- a modified 1st class lever
moving pulley- wheel is free to move block and tackle- a system of both above MA = number of ropes |
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wheel and axle
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a machine consisting of 2 wheels and different sizes that rotate together
IMA = rw / ra |
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inclined plane
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IMA = length of slope / height of slope
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screw
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an inclined plane wrapped around a cylindrical post
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wedge
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an inclined plane w/ one or 2 sloping side
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thermal energy
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the sum of the kinetic and potential energy of all the molecules in an object
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conduction
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the transfer of thermal energy by direct contact
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convection
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the transfer of thermal energy by fluids
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radiation
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the transfer of energy in electromagnetic waves
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