Motion Motion
Jan 16, 2016
MotionMotion
Where does the car have Where does the car have the most potential the most potential energy?energy?
a)a) Between A and Between A and BB
b)b) Between B and Between B and CC
c)c) Between C and Between C and DD
d)d) After DAfter D
Where does the car have Where does the car have more kinetic energy than more kinetic energy than potential?potential?
a)a) AA
b)b) BB
c)c) CC
d)d) DD
Describing MotionDescribing Motion
1)1) SpeedSpeed = rate at which an object = rate at which an object
moves moves (“how(“how fastfast”)”)
Describing MotionDescribing Motion
1)1) SpeedSpeed = rate at which an object moves = rate at which an object moves (“how (“how fastfast”)”)
speed equation:speed equation: speed = distance speed = distance ÷ time÷ time ((v = d ÷ tv = d ÷ t))
distancedistance = “how = “how far”far” object traveled object traveledtimetime = “how = “how long”long” object traveled object traveled
units of speed:units of speed: meters per second (meters per second (m/sm/s) or ) or kilometers per hour kilometers per hour
((km/hrkm/hr))
A jogger runs the first 1000 m of a race in 250 A jogger runs the first 1000 m of a race in 250 sec. What is the jogger’s speed?sec. What is the jogger’s speed?
What is the correct way to plug in the What is the correct way to plug in the numbers?numbers?
a)a) v = 250 sec v = 250 sec ÷ 1000 ÷ 1000 mm
b)b) v = 1000 m v = 1000 m ÷ 250 ÷ 250 secsec
c)c) v = 1000 m xv = 1000 m x 250 250 secsec
d)d) v = 250 sec xv = 250 sec x 1000 1000 mm
Describing MotionDescribing Motion
1)1) SpeedSpeed = rate at which an object moves = rate at which an object moves
speed = distance speed = distance ÷ time ÷ time (v = d ÷ t)(v = d ÷ t)
A jogger runs the first 1000 m of a race A jogger runs the first 1000 m of a race in 250 sec. What is the jogger’s speed?in 250 sec. What is the jogger’s speed?
v = 1000 m ÷ 250 secv = 1000 m ÷ 250 sec
A jogger runs the first 1000 m of a race A jogger runs the first 1000 m of a race in 250 sec. in 250 sec. What is the jogger’s speed?What is the jogger’s speed?
a)a) v = 0.25 m/secv = 0.25 m/sec
b)b) v = 0.25 sec/mv = 0.25 sec/m
c)c) v = 4 m/secv = 4 m/sec
d)d) v = 4 sec/mv = 4 sec/m
Describing MotionDescribing Motion
1)1) SpeedSpeed = rate at which an object moves = rate at which an object moves
speed = distance speed = distance ÷ time ÷ time (v = d ÷ t)(v = d ÷ t)
A jogger runs the first 1000 m of a race A jogger runs the first 1000 m of a race in 250 sec. What is the jogger’s speed?in 250 sec. What is the jogger’s speed?
v = 1000 m ÷ 250 v = 1000 m ÷ 250 secsec
v = 4 m/secv = 4 m/sec
Distance-Time GraphsDistance-Time Graphs
Distance-Time Distance-Time
GraphsGraphs = used = used
to to representrepresent a a
person or person or
object’s motionobject’s motion
How long had both boys been running How long had both boys been running before they met?before they met?
a)a) 4 sec4 sec
b)b) 2.7 sec2.7 sec
c)c) 27 yards27 yards
d)d) 20 yards20 yards
How far did the red boy run before he How far did the red boy run before he met the blue boy?met the blue boy?
a)a) 40 yards40 yards
b)b) 27 yards27 yards
c)c) 2.7 sec2.7 sec
d)d) 20 yards20 yards
What was the blue boy’s speed?What was the blue boy’s speed?
a)a) 20 yards20 yards
b)b) 5 yds/sec5 yds/sec
c)c) 20 yds/sec20 yds/sec
d)d) 10 yds/sec10 yds/sec
Describing MotionDescribing Motion
1)1) Speed Speed = rate at which an object moves= rate at which an object moves
2)2) VelocityVelocity = speed with a specific = speed with a specific directiondirection
A running back moves towards the east end A running back moves towards the east end zone at 10 m/sec. What is the running back’s zone at 10 m/sec. What is the running back’s
velocityvelocity??
a)a) 10 m/sec10 m/sec
b)b) 10 m/sec west10 m/sec west
c)c) 10 m/sec east10 m/sec east
d)d) 10 meters east10 meters east
Describing MotionDescribing Motion
1)1) SpeedSpeed = rate at which an object = rate at which an object movesmoves
2)2) VelocityVelocity = speed with a specific = speed with a specific directiondirection
3)3) AccelerationAcceleration = change in = change in velocity velocity over over timetime
Describing MotionDescribing Motion
3)3) AccelerationAcceleration = change in = change in velocity over timevelocity over time
– Acceleration can mean:Acceleration can mean: Speeding up Speeding up = = positive (+) positive (+)
accelerationacceleration
Describing MotionDescribing Motion
3)3) AccelerationAcceleration = change in = change in velocityvelocity
– Acceleration can mean:Acceleration can mean: Speeding up = Speeding up = positive (+)positive (+)
accelerationacceleration
Slowing down Slowing down == negative (-) negative (-) accelerationacceleration
Describing MotionDescribing Motion
3)3) AccelerationAcceleration = change in velocity = change in velocity– Acceleration can mean:Acceleration can mean:
Speeding up = Speeding up = positive (+)positive (+) accelerationacceleration Slowing downSlowing down == negative (-)negative (-) accelerationacceleration
Changing directionChanging direction
– Think of a Think of a rollercoasterrollercoaster because it can because it can do all three!do all three!
Which car is not Which car is not accelerating?accelerating?
a)a) A car driving up a hill A car driving up a hill and down the other side.and down the other side.
b)b) A car turning a corner.A car turning a corner.
c)c) A car turning a corner at A car turning a corner at a constant speed.a constant speed.
d)d) A car driving at a A car driving at a constant speed along a constant speed along a straight highway.straight highway.
Which is NOT an Which is NOT an example of example of acceleration?acceleration?
a)a) As you see your As you see your friend, you jump up friend, you jump up and run to greet and run to greet them.them.
b)b) Your dog runs in Your dog runs in circles chasing his tail.circles chasing his tail.
c)c) You pedal your bike You pedal your bike along your street at 5 along your street at 5 km/hr.km/hr.
d)d) A car slows down as it A car slows down as it comes to a red light. comes to a red light.
Describing MotionDescribing Motion
3)3) AccelerationAcceleration = change in velocity over = change in velocity over time time
acceleration equation:acceleration equation: acceleration = velocity acceleration = velocity ÷ time÷ time ( (a = v ÷ ta = v ÷ t))
units of acceleration:units of acceleration: m/s per second (m/s per second (m/sm/s22) )
or or km/hr per hour (km/hr per hour (km/hrkm/hr22))
You’re running late, so you accelerate from 0 to 72 You’re running late, so you accelerate from 0 to 72 km/hr in 8 sec. What is your acceleration?km/hr in 8 sec. What is your acceleration?
What is the correct way to plug in the What is the correct way to plug in the numbers?numbers?a)a) a = 72 km a = 72 km ÷ 8 sec÷ 8 sec
b)b) a = 0 km/hr a = 0 km/hr ÷ 8 ÷ 8 secsec
c)c) a = 72 km/hr a = 72 km/hr ÷ 8 ÷ 8 secsec
d)d) a = 8 sec ÷ 72 a = 8 sec ÷ 72 km/hrkm/hr
3)3) AccelerationAcceleration = change in velocity = change in velocity
acceleration = velocity acceleration = velocity ÷ time÷ time (a = v ÷ (a = v ÷ t)t)
You’re running late, so you You’re running late, so you accelerate from 0 to 72 km/hr in 8 accelerate from 0 to 72 km/hr in 8 sec. What is your acceleration?sec. What is your acceleration?
a = 72 km/hr ÷ 8 sec. a = 72 km/hr ÷ 8 sec.
Describing MotionDescribing Motion
You’re running late, so you accelerate from 0 to You’re running late, so you accelerate from 0 to 72 km/hr in 8 sec.72 km/hr in 8 sec. What is your What is your
acceleration?acceleration?
a)a) 9 km/hr9 km/hr
b)b) 9 km/hr/sec9 km/hr/sec
c)c) 9 km/hr/hr9 km/hr/hr
d)d) 9 km9 km
AccelerationAcceleration = change in velocity = change in velocity
acceleration = velocity acceleration = velocity ÷ time÷ time (a = v ÷ t) (a = v ÷ t)
A car accelerates from 0 to 72 km/hr in A car accelerates from 0 to 72 km/hr in 8 sec. What is the car’s acceleration?8 sec. What is the car’s acceleration?
a = 72 km/hr ÷ 8 sec. a = 72 km/hr ÷ 8 sec.
a = 9 km/hr/sa = 9 km/hr/s
Describing MotionDescribing Motion
You see a police car and slow down from 72 km/hr You see a police car and slow down from 72 km/hr to 62 km/hr in 2 sec. to 62 km/hr in 2 sec. What is your acceleration?What is your acceleration?
What is the correct way to plug in the What is the correct way to plug in the numbers?numbers?
a)a) a = 72 km a = 72 km ÷ 2 sec÷ 2 sec
b)b) a = 10 km/hr a = 10 km/hr ÷ 2 ÷ 2 secsec
c)c) a = -10 km/hr a = -10 km/hr ÷ 2 ÷ 2 secsec
d)d) a = 62 km/hr a = 62 km/hr ÷ 2 ÷ 2 secsec
3)3) AccelerationAcceleration = change in velocity = change in velocity
acceleration = velocity acceleration = velocity ÷ time÷ time (a = v ÷ (a = v ÷ t)t)
You see a police car and slow down You see a police car and slow down from 72 km/hr to 62 km/hr in 2 sec. from 72 km/hr to 62 km/hr in 2 sec. What is your acceleration?What is your acceleration?
a = -10 km/hr ÷ 2 sec. a = -10 km/hr ÷ 2 sec.
Describing MotionDescribing Motion
You see a police car and slow down from 72 You see a police car and slow down from 72 km/hr to 62 km/hr in 2 sec.km/hr to 62 km/hr in 2 sec. What is your What is your
acceleration?acceleration?
a)a) -5 km/hr-5 km/hr
b)b) -5 km/hr/sec-5 km/hr/sec
c)c) 5 km/hr/sec5 km/hr/sec
d)d) 0.5 km/hr/sec0.5 km/hr/sec
AccelerationAcceleration = change in velocity = change in velocity
acceleration = velocity acceleration = velocity ÷ time÷ time (a = v ÷ t) (a = v ÷ t)
You see a police car and slow down You see a police car and slow down from 72 km/hr to 62 km/hr in 2 sec. from 72 km/hr to 62 km/hr in 2 sec. What is your acceleration?What is your acceleration?
a = -10 km/hr ÷ 2 sec. a = -10 km/hr ÷ 2 sec. a = -5 km/hr/sa = -5 km/hr/s
Describing MotionDescribing Motion