Physical Science: Chapter 2 Motion

Term
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when an object changes position over time when compared with a reference point
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Terms in this set (42)
when an object changes position over time when compared with a reference point
motion
object that appears to remain in place
reference point
coordinate system in which the position is measured
frame of reference
In what SI unit(s) are distances measured?
meter, centimeter, kilometer, decameter, decimeter
how far an object has moved
distance
distance and direction an object's change in position is from the starting point
displacement
Give two examples of reference points.
building, tree, homes, mountains, beaches, the border
distance an object travels per unit of time
speed
What two items are needed to find the speed of an object?
distance and time
What is the SI unit for speed?
meters / second (m/s)
How do you find average speed?total distance divided by total timeWhy is speed an average rate?travel is NOT constantspeed given at a specific point in timeinstantaneous speedHow do you find instantaneous speed?look at a speedometerOn a distance-time graph, what is the independent variable?timeOn a distance-time graph, what is the dependent variable?distanceOn a distance-time graph, what is on the x-axis?timeOn a distance-time graph, what is on the y-axis?distanceIf an object moves at constant speed, what would a distance-time graph look like?a straight line increasing upwardWhat does the slope on a distance-time graph tell you?speed of the object (d/t)What does a horizontal line represent on a distance-time graph?the object is at rest / not movingWhat does a vertical line represent on a distance-time graph?can NOT existthe speed of an object in a particular directionvelocityHow is velocity different than speed?velocity has direction AND speedWhen is velocity constant?when an object is moving in a straight line at a constant speedGive an example of constant velocity.riding a bike at a constant speed without changing directionHow do we know the Earth's crust moves?We use satellites and frame of references / distances are much smaller so a larger frame of reference is neededthe rate of change of velocity as time changesaccelerationGive an example of an acceleration.a car stopping or speeding up / a thrown ball fallingWhat is the SI unit for acceleration?m/s/sacceleration in which the velocity increases from start to end or acceleration is in the same direction as velocitypositive accelerationacceleration in which the velocity decreases from start to end or acceleration is in opposite direction as velocitynegative accelerationWhat are the two requirements for velocity?speed AND directionHow do you calculate acceleration?A = (vf - vi) / tGive an example of something with positive acceleration.bike coasting down a hill, ball/rock falling, car acceleratingWhat does a change in direction do to acceleration?causes an accelerationExplain whether an acceleration is occurring: coasting on a roller coaster ride.yes, change in directionExplain whether an acceleration is occurring: driving 15 m/h east.No, no change in direction or speedExplain whether an acceleration is occurring: walking around the football field.Yes, change in directionDetermine the speed if an object moves 25 meters in 19 seconds left.25 / 19 = 1.3 m/sDetermine the distance if the speed is 15 m/s and the object moved for 25 seconds.375 m = dDetermine the acceleration if a car has a velocity at the start of 10 m/s and it accelerates to 60 m/s in 5 seconds.10 m/s/s