position-time graphs & speed-time graphs year 12 unit 1 module 1 lesson 5
TRANSCRIPT
POSITION-TIME GRAPHS &
SPEED-TIME GRAPHSYEAR 12
UNIT 1
MODULE 1
LESSON 5
UNIFORM VELOCITY - CONSTANT
•REMINDER
•VELOCITY = DISPLACEMENT / TIME
•V = S/T
•THEREFORE
•DISPLACEMENT = VELOCITY X TIME
•S= V T
UNIFORM VELOCITY - CONSTANT
•REMINDER
•ACCELERATION = CHANGE IN VELOCITY / TIME
•A=(V-U)/T
•THEREFORE
•V=U+AT
UNIFORM VELOCITY - CONSTANT
•REMINDER
•ALSO, REMEMBER INSTANTANEOUS AND AVERAGE VELOCITIES
•AND DIFFERENCES BETWEEN DISPLACEMENT AND DISTANCE
Draw a set of axes. Time in seconds along the x-axis. Displacement in metres up the y-axis. Draw up to 10 on both axes.
• DRAW THE FOLLOWING: A LINE ON THE GRAPH TO REPRESENT:
• A) STOOD STILL AT POSITION, 0M
• B) STOOD STILL AT 3M
• C) WALKING STEADILY AT 1M/S, STARTING AT POSITION 0M
• D) WALKING STEADILY AT 4M/S, STARTING AT POSITION 2M
• E) ACCELERATING WHILST WALKING FORWARD
(DON’T WORRY ABOUT NUMBERS, JUST SHOW ME THE RIGHT SHAPE OF LINE)
• F) DECELERATING WHILST WALKING FORWARD
• G) STARTING AT 10M AND WALKING AT 2M/S BACK TO THE START POINT (0M)
• H) WALKING FORWARDS AT 2M/S FOR 3 SECONDS, AND THEN STANDING STILL FOR 4 SECONDS, BEFORE RUNNING BACK TO THE START POINT (0M) AT 6M/S
• ON YOUR PAPER (AS OPPOSE TO WHITEBOARDS), TRY TO DRAW ALL THE SEPARATE LINE ELEMENTS FOR A DISPLACEMENT-TIME GRAPH
• E.G. STEADY POSITIVE VELOCITY
A few of the possible lines on a displacement – time graph. Can you think of any others?
EACH TYPE OF MOTION ON A DISPLACEMENT-TIME GRAPH
• SLIDE COMING SOON, TO A WHIEBOARD NEAR YOU!
• (PROBABLY JUST WANT TO WRITE THEM DOWN FOR NOW)
15/09/06
DISCUSS IN PAIRS, WRITE YOUR ANSWER ON YOUR WHITEBOARDS:
• WHAT WOULD LOOK DIFFERENT ON A DISPLACEMENT-TIME GRAPH TO A DISTANCE-TIME GRAPH?
• NEGATIVE DISPLACEMENT. (I.E. MOVING BACK TOWARDS WHERE YOU STARTED), TECHNICALLY SPEAKING, ON A DISTANCE-TIME GRAPH, YOU CANNOT HAVE A NEGATIVE DISTANCE, AS DISTANCE IS A SCALAR.
• TAYA WALKS A STEADY VELOCITY FOR 15 SECONDS, FOR 60M
• SHE THEN STAYS STATIONARY FOR 20 SECONDS
• AND THEN WALKS A STEADY VELOCITY FOR 5 MORE SECOND, FOR 10M
• SHE THEN RETURNS THE 70M HOME OVER 60 SECONDS, BY WALKING AT A STEADY SPEED
• DRAW THIS DISPLACEMENT-TIME GRAPH
• HOW CAN YOU FIND TAYA’S VELOCITY AT A GIVEN POINT IN HER JOURNEY FROM THIS GRAPH?
THE GRADIENT OF DISPLACEMENT-TIME GRAPH IS VELOCITY!!!!!!!!!!!!!!!!!
BECAUSE:
GRADIENT = CHANGE IN Y / CHANGE IN X
= CHANGE IN DISPLACEMENT / CHANGE IN TIME
= CHANGE IN VELOCITY
WHAT WOULD THE GRADIENT OF A DISTANCE-TIME GRAPH BE?
• -GO THROUGH MOTION GRAPH QUESTION ON BASELINE TEST
EXAM QUESTIONS
ANSWERS
WALKING DISPLACEMENT-TIME GRAPHS
SPEED-TIME & VELOCITY-TIME GRAPHS
LOOK AT ALL YOUR POSSIBLE LINES FROM DISPLACEMENT-TIME GRAPH.
• WHAT WOULD THEY LOOK LIKE ON A VELOCITY-TIME GRAPH?
• CAN YOU ADD ANY MORE LINES?
EACH TYPE OF MOTION ON A VELOCITY-TIME GRAPH
• SLIDE COMING SOON, TO A WHIEBOARD NEAR YOU!
• (PROBABLY JUST WANT TO WRITE THEM DOWN FOR NOW)
• (ALMOST AS MUCH OF AN ANTI-CLIMAX AS THE FIRST TIME I SHOWED THIS SLIDE)
15/09/06
Template copyright www.brainybetty.com 2005 2815/09/06
•
•Draw a displacement –time graph for bob’s journey. Distance should be along the y-axis, and time on the x-axis
•Bob is out for a walk. He starts travelling at 0.5m/s for 20 secs• He then jogs on for 10 secs at a speed of 5m/s• He then stops for 10 seconds to remember what he forgot but can't.• He suddenly remembers what it was and walks back at for 20 secs at 3m/s
• DRAW THE SPEED-TIME GRAPH FOR BOB’S JOURNEY
• WHAT DOES THE GRADIENT OF THIS GRAPH TELL US ABOUT A GIVEN PARTO F HIS JOURNEY?
• HOW CAN WE FIND THE DISTANCE TRAVELLED FROM THIS GRAPH?
• GRADIENT OF A VELOCITY-TIME GRAPH IS ACCELERATION
• AREA UNDERNEATH THE GRAPH IS DISTANCE TRAVELLED
SPEED-TIME GRAPHS IN TERMINATOR 2(ONE OF THE TERMINATOR FILMS THAT
DIDN’T SUCK… I’M LOOKING AT YOU TERMINATOR 3)
• HTTP://WWW.YOUTUBE.COM/WATCH?V=4DERTTFCTB4
• RECORD THE TIME THAT EACH FO THE EVENTS HAPPEN IN THE CHASE AND FIL LTHEM IN ON THE SHEET. FROM HERE WE CAN PLOT A SPEED-TIME GRAPH
HOMEWORK
EXTRA SLIDES
• ADD HOMEWORK
• ADD EXAM QUESTIONS
• SORT OUT PICTURES OF ALL LINE ELEMENT SLIDES
• GATHER RESOURCES E.G. TERMINATOR ONES
• HOW CAN WE WORK OUT VELOCITY FROM A DISPLACEMENT-TIME GRAPH?
• VELOCITY IS RATE OF CHANGE OF POSITION.
• WE NEED TO FIND OUT HOW RAPIDLY THE POSITION IS CHANGING
• OUR GRAPH LETS US DO THIS EASILY – IT’S SIMPLY THE GRADIENT!!!
• WHAT ABOUT DISTANCE-TIME GRAPHS?
• CAN WE HAVE A NEGATIVE VALUE ON A DISTANCE-TIME GRAPH?
• NO – DISTANCE IS JUST THE PATH TAKEN, IT HAD NO DIRECTION, HENCE NEGATIVE DISTANCE DOESN’T REALLY MEAN ANYTHING
• WHAT WOULD THE GRADIENT OF A DISTANCE-TIME GRAPH BE?
• SPEED, SPEED = DISTANCE/TIME
• WRITE 3 QUESTIONS ON A PIECE OF PAPER. ANYTHING FROM THIS LESSON…