Setting up and executing an experiment QPOE 2 Question Prediction Evaluate Observation Explanation Knowledge probe What do you know about the given question Investigation plan How will you investigate ID: 730282
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Slide1
Coefficient of Friction
Setting up and executing an experiment.Slide2
QPOE
2
Question
Prediction
Evaluate
Observation
Explanation
Knowledge probe
What do you know about
the given question
Investigation plan
How will you investigate
the question
Data Analysis
How will you analyze
your data
Application
How will you apply
what you foundSlide3
Q
UESTION
Which of the following objects has the greatest coefficient of rolling friction between itself and the carpet floor?Slide4
What have we learned that would help us answer this question?
The coefficient of static and sliding friction activity showed us that we can calculate
m
by dividing the friction force by the normal force (mass x acceleration due to gravity).Slide5
When an object is rolling, the only force on the object is the friction force between the object and its surface of contact. This means that the net Force is equal to the friction force.
Newton’s 2
nd
Law of Motion Friction force equation
So to calculate the coefficient of rolling friction, take the acceleration of the rolling object and divide by acceleration due to gravitySlide6
Equations of Motion for Uniform Acceleration
Equations Variables
v
f = v
i + at vi vf a t
d = ½ (vf + vi) t v
i vf d td =
vit + ½ at2 vi a d t
v
f 2 =
vi 2 + 2ad vi
vf a dSlide7
Knowledge Probe
What do we know about friction?
How do we calculate the coefficient of friction?
Which kinematic equations would help us?What materials do we need?What values are we going to measure?
What types of errors should will we encounter?How many measurement should we take?Slide8
P
REDICTION
Which object would have the greatest coefficient of rolling friction between itself and the carpet floor?
Tennis ball, Marble, steel sphere, racquetballWhy? Justify your prediction.
Tennis ball – rough fuzzy surfaceMarble – smooth all aroundSteel sphere – heavy, smooth, slow to startRacquetball – smooth, kinda heavySlide9
Investigative plan
Determine the procedures with which we can obtain the values needed in the knowledge probe which in turn will answer the QUESTION.
Material list: ball, ramp, stopwatch, meter stick, carpeted area, pencil and paper, calculator
Procedure:1. Find the area to conduct the experiment
2. Gather the materials3. Set up the experiment with the height being 15 cm4. Release the ball from the top of the ramp5. Measure the distance from the bottom of the ramp to where it stops.
6. Measure the time from the bottom of the ramp to when it stops7. Record the data in the table8. Repeat the process 5 times9. Slide10
O
BSERVATION
What values are measured?
How many times do we repeat the trials?
Object: Tennis Ball
displacementtimeTrial 1
Trial 2Trial 3
Trial 4
Trial 5Slide11
Data analysis
What information can be derived from the observation?
Object:
Tennis Ball
displacement
timeInitial velocityacceleration
Trial 1
Trial 2Trial 3
Trial 4Slide12
E
VALUATION
Using the acceleration that was calculated rom the data analysis, determine the coefficient of friction.
Object:
Tennis Ball
displacementtime
Initial velocityaccelerationCoefficientmTrial
1Trial 2
Trial 3
Trial 4Slide13
E
XPLANATION
From the evaluation, ______________ has the greatest rolling coefficient of friction.
Offer reasons why the object has the greatest rolling friction.1.2.3.
4.