Download Motion

ICP
TCHS
“Motion”
Students who demonstrate
understanding can:
Analyze data to support the claim that Newton’s
second law of motion describes the mathematical
relationship among the net force on a macroscopic
object, its mass, and its acceleration. [Clarification
Statement: Examples of data will include tables or
HSgraphs of position or velocity as a function of time
PS2-1. for objects subject to a net unbalanced force, such
as a falling object, an object rolling down a ramp, or
a moving object being pulled by a constant force.]
[Assessment Boundary: Assessment is limited to
one-dimensional motion and to macroscopic
objects moving at non-relativistic speeds.]
What is motion?
 motion
- a constant change in position
 distance - the result of motion in any
direction
 displacement - the result of motion in a
particular direction(sign indicates direction)
 scalar - a quantity having magnitude only
 vector - a quantity having magnitude and
direction
Speed or Velocity?
 speed
- the time rate of change in distance
 velocity - the time rate of change in
displacement
 Speed is a scalar. Why?
 Velocity is a vector. Why?
 For now, we will use the terms speed and
velocity without regard to direction.
Sample Problem
 Suppose
you drive 30 miles in 0.5 hours. What is
your average speed in mi/hr? ft/s?
 How did you estimate your answer to the first part
of the question?
 How can you calculate the answer to the second part
of the question?
 Page 72, Practice Problems 1,2 in notes
Acceleration
 acceleration
- the time rate of change in
velocity
 a = (vf - vi ) / t
 A car moving at 25m/s increases to 55m/s in 5
seconds. Find its rate of acceleration.
 a = (55m/s - 25m/s)/5s = (30m/s)/5s = 6m/s2
 What does negative acceleration indicate?
Experiment
 You
will roll a ball down an incline and measure the
time required for it to roll 0-10cm, 0-20cm, etc up to
0-100cm. Make three trials and average each.
 Record all average values in a data table.
 Plot a graph of x vs t.
 Analyze the graphs with regards to constant and
varying slopes.
 Write a report for this experiment.
2-3 Falling Objects
 When
gravity acts on an object, the object
is accelerated at the rate of 9.8m/s2,
980cm/s2 , or 32ft/s2. These numbers are
constant and should be memorized. Any
time free fall is involved, a in an equation
should be replaced with g, the acceleration
due to gravity.
 Page 80, 1-7
Lab Report Format
40 pts-due next class meeting after lab is completed
 Upon
completion of each experiment, you will turn
in a lab report using the following format. The
report will be referred to as a ppoc.
 p - Purpose - usually one statement
 p - Procedure - steps which will duplicate what you
have done, you may use diagrams
 o - Observation - includes data (use data table when
possible) and calculations
 c - Conclusion - what you learned, possible reasons
for error, suggestions for improvement and opinion
Experiment
 You
will roll a golf ball down an incline and
measure the time required for it to roll 0-10cm, 020cm, etc up to 0-100cm. Make three trials and
average each.
 Record all average values in a data table.
 Plot
a graph of x vs t. Plot a graph of v vs t.
Analyze
the graphs with regards to constant
and varying slopes.
Write a lab report for this experiment.
Plotting Graphs
 1.
Identify the independent and dependent variables.
 2. Choose the appropriate range and plot the independent
variable values on the x-axis and dependent on the y-axis.
 3. Decide if the origin is an appropriate point.
 4. Number and label the horizontal axis.
 5. Repeat steps 2-4 for the dependent variable.
 6. After plotting all points, draw the best fitting line
through as many points as possible.
 7. Give the graph a title that best describes what it
represents.
Content Terms
Vocabulary
 motion
 distance
 displacement
 speed
 velocity
 acceleration
 scalar
 vector