PHYSICS. MOTION ENDURING UNDERSTANDINGS: An object is in motion if its distance from a reference...
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Transcript of PHYSICS. MOTION ENDURING UNDERSTANDINGS: An object is in motion if its distance from a reference...
PHYSICSPHYSICS
MOTIONMOTION
ENDURING UNDERSTANDINGS:ENDURING UNDERSTANDINGS:
• An object is in motion if its distance from a An object is in motion if its distance from a reference point is changing. reference point is changing.
• Speed is the distance traveled divided by the time Speed is the distance traveled divided by the time traveled. V = d traveled. V = d tt
• Acceleration is the rate at which velocity changes. Acceleration is the rate at which velocity changes.
INTERNATIONAL SYSTEM OF UNITSINTERNATIONAL SYSTEM OF UNITS
• The SI is based on the number 10. The SI is based on the number 10.
• The basic unit of length is the meter The basic unit of length is the meter
• The basic unit of volume is the liter The basic unit of volume is the liter
• The basic unit of mass is the gramThe basic unit of mass is the gram
• The basic unit of temperature is CelsiusThe basic unit of temperature is Celsius
THE METRIC LADDERTHE METRIC LADDER
kilokilo
hect
ohe
cto
deko
deko
met
er, l
iter
met
er, l
iter
cent
ice
nti
mill
im
illi
deci
deci
11 .1.1 .01.01 .001.00110101001001,0001,000
RELATIVE MOTIONRELATIVE MOTION• Relative Motion depends on your point of view. Relative Motion depends on your point of view.
• An object is in motion if its distance from a reference An object is in motion if its distance from a reference point is changing. point is changing.
Stand perfectly still. Are you in motion?Stand perfectly still. Are you in motion? From your point of view – no.From your point of view – no.
But if viewed from space, you would be moving at But if viewed from space, you would be moving at
about 1,000 mph with the rotation of the Earth!about 1,000 mph with the rotation of the Earth!
SPEEDSPEED• Speed is the distance traveled divided by the time.Speed is the distance traveled divided by the time.
speed = distance / timespeed = distance / time
• Average speed = total distance / total time: add all the Average speed = total distance / total time: add all the distances and divide by the total time.distances and divide by the total time.
32 km + 13 km = 45 km32 km + 13 km = 45 km 2 hrs + 1 hr = 3 hrs2 hrs + 1 hr = 3 hrs
• Instantaneous speed is the rate an object is moving at a Instantaneous speed is the rate an object is moving at a given instant in time.given instant in time.
45 km / 3 hrs = 15 km/hr45 km / 3 hrs = 15 km/hr
ACCELERATIONACCELERATION• Acceleration is any change in speedAcceleration is any change in speed
• Acceleration can be a decrease in speed, Acceleration can be a decrease in speed, increase in speed, or a change in directionincrease in speed, or a change in direction
Try it . . .Try it . . .• Sam rides his bike 4 miles to Sylvan’s house. It takes Sam rides his bike 4 miles to Sylvan’s house. It takes
him 20 minutes. What was Sam’s average velocity?him 20 minutes. What was Sam’s average velocity? V = 4 mi / 20 min V = 4 mi / 20 min V = .2 mi/minV = .2 mi/min
• What is Sam’s velocity in miles per hour?What is Sam’s velocity in miles per hour?
V = x = 12.0 mi/hrV = x = 12.0 mi/hr.2 mi.2 mi1 min1 min
60 min60 min 1 hr1 hr
• If Sylvan rode to Sam’s house averaging 15 mi/hr, how long If Sylvan rode to Sam’s house averaging 15 mi/hr, how long would it take him to go the 4 miles?would it take him to go the 4 miles?
T = = .2666hrT = = .2666hr
• How many minutes did it take Sylvan?How many minutes did it take Sylvan?
T = .2666hr x = 16 min T = .2666hr x = 16 min
• What was Sylvan’s speed in kilometers per hour? What was Sylvan’s speed in kilometers per hour?
x = 24.15 km/hrx = 24.15 km/hr
4 mi4 mi
15mi/hr15mi/hr
60 min60 min
1 hr1 hr
15mi15mi
1hr1hr
1.61km1.61km
1mi1mi