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Science 1 and 2
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Gravity
Terms in this set (41)
what is motion
an objects Change in position relative to a reference point
frame of reference
the objects used to define motion- objects that make up a frame of reference are treated as if they are not moving
when an object changes position with respect to a frame of reference,
the object is in motion
scientists describe how far an object has moved using what
distance and displacement
distance
who far an object moves- measures the path being takes
displacemnt
measure of how far the starting point is from the ending point (need direction and length) Need to know ending and starting point and the direction in which an object moves.
which is shorter
displacement is shorter unless you are traveling in a straight lien
when you describe distance and displacement what do you need
length and direction (north south east west)
speed
describes how far an object travels in a certain amount of time (how fast)
velocity
describes both how fast an object is moving and in what direction it is moving (speed in a given direction)
velocity is described
relative to a refereance point
how is the direction of a velocity described
positive or negative. if an object is moving in one direction, it has a positive velocity. if the object then moves the opposite direction, it has a negative velocity
combined velocities determine the
resultant velocity
speed describes
the distance an object travels over a certain amount of time
what 2 quantities do you need
the distance traveled and the time it took
constant speed
an object covers equal distance in equal amounts of time
how do you calculate average speed
take the full distance and divide it by the full time
instantanious speed
speed at a given instant or time
why can't you use the speed equation to calculate instantaniosu speed
because we cannot divide by 0- if an object is moving at a constant speed its instantaneous speed is equal to its constant speed
how do you calculate velocity
find the speed of the object and the direction in which it is traveling
how can you show motion on a graph
recording distance vs time (time on x)- use shape of line to learn about the motion
on a graph of distance vs time, the motion of an object moving at a constant speed is
a straight line. the slope is equal to the speed of the object. slope is speed on a distance vs time
slope =
vertical change/horrizontile change
on a graph of distance vs time, the motion of an object moving at variable speed is a
curved line
acceleration
occurs when an object changes velocity- rate at which velocity changes overtime -change in speed or direction
just like velocity has both a speed and a direction,
acceleration has a value and a direction- when the speed or direction of an object changes, it is accelerating
object speeding up=
positive acceleration
object slowing down=
negative acceleration
when an object undergoes an acceleration, what changes
its velocity
why is changing direction considered accelerating?
bc acceleration is defined as the rate at which velocity changes with time- velocity includes speed and direction, so an object accelerates if its speed, direction, or both changes
you are constantly accelerating in a
circular motion- direction always changing
centripetal acceleration
the acceleration that occurs when an object moves in a circular path- velocity always changing due to direction, hence, acceleration
how are we all experiencing centripetal acceleration right now
earth is rotating on its axis. as earth rotates, its surface - and everything on it- travels in a circular path
for an object moving in a straight line, how does acceleration occur
speed up or slow down- therefore, you can calculate the objects acceleration if you know its speed at 2 different times.
how do you calculate acceleration
final speed-initial speed
----------------------------
time
if the acceleration is small,
the velocity is changing slowly. and if it is big, the velocity is changing much faster
adverage acceleration is calculated by-
dividing the change in the objects velocity by the time over which the change occurred
you can deterring an objects acceleration by looking at a graph of
speed vs time
a straight line on a speed vs time graph indicates
a constant acceleration
constant acceleratoin
acceleration that does not change with time- slope=acceleration on this graph
on a graph of distance vs time what kinda of line indicates acceleration
curved
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