Graphing and Problem Solving Friday, August 29, 2014

Friday, 8/29 Unit1: Tools for Physics  If this is your first time to class come see me at the door and show me your schedule.  Pick up a sheet from the Physics bin  Complete the warm up sheet (you will have 3 minutes to complete).  Upcoming dates  ‘A’ day Unit 1 test - Wednesday, 9/3  ‘A’ day Unit 2 test – Wednesday, 9/17  Last day to turn in 1SW extra credit – Friday, 9/19

Sharing your experience Discuss your warm- up with a partner

Warm - up 1. Draw a graph below and title it Position time Graph, label the x-axis as time, and the y-axis as distance. Label the y-axis in 10 meter increments to 50 meters and the x- axis in 1 second intervals to 10 seconds. 2. We are going to roll a bowling ball and collect time data as the ball passes certain distances. Will the force applied to the ball influence the velocity of the bowling ball? Explain your answer.

Lab expectations  Stay on task  Students are working keep… your voice at a low conversation level.  Absolutely no horse play.

What you need  Sticky note  Timer  Something to write with  I need a volunteer

Graphing Instructions 1. Title your graph – Position vs Time graph 2. Label your Y-axis distance (m) 3. Label your X-axis time (s) 4. Time should be in.5 s increments up to 15 s 5. Distance should be in 1 meter increments up to Plot the point for the fast ball data (use a colored pencil). Draw a best fit line and label the line fast ball. 7. Plot the point for the slow ball data (use a different colored pencil). Draw a best fit line and label the line fast ball. 8. Plot the point for the reverse ball data (use a different colored pencil). Draw a best fit line and label the line fast ball.

On the back of your graph respond to the question below 1. How did the slope (steepness) of the lines compare to each other? 2. Describe the direction of the ball during each of the three rolls. 3. What role do you think force and mass played in this experiment?

On the back of your graph respond to the question below 1. How did the slope (steepness) of the lines compare to each other? Visually the fast bowl, then reverse bowl, then slow bowl. The slope of line tells how fast the object is moving. Steeper = greater velocity. 2. Describe the direction of the ball during each of the three rolls. Considering the zero meter mark was the point of reference…the fast and slow bowl were moving away from the reference point. The reverse bowl was moving towards the reference point. 3. What role do you think force and mass played in this experiment? When I applied a greater force the ball went faster. If the mass of the ball increased then I would need to apply a greater force to keep the velocity of the ball the same. Let’s go further….What is mass? Are mass and weight the same.

 Discussion  Mass is matter.  In order for mass to change the original object must be changed (chemical reaction, physical modification of its state).  Weight is a function of mass and the effect of gravity.  Weight can change based on the gravitational force.  Example: my mass on earth and the moon are the same but I weigh less on the moon than on the earth.

GUESS Method  Method for solving word problems  Given:  relevant information  clearly labeled symbol and units  Unknown:  Identify what the problem is asking you to solve for  clearly labeled with symbol  Equation:  Write it using only symbols  Substitution:  Substitute given information into your equation  Solve:  Solve algebraically for your unknown term

TermSymbol/VariableUnitsExample Stem of Question Distancedm 5 m How far…? Displacementdm 3 m north How far (and what direction) from start…? Speedvm/s 27 m/s How fast…? Velocity (speed w/direction) vm/s -43 m/s How fast and what direction…? (direction can be shown with + or -) Accelerationa m/s m/s 2 -What is the change in velocity? -What is the acceleration? Timets 7.3 s How long…? Initial speed or Initial velocity vivivivim/s How fast is the object moving at first? Final speed or Final velocity vfvfvfvfm/s How fast is the object moving at the end?

Applying GUESS to velocity Given distance and time solve for velocity.

Example: Sheldon from the ‘Bing Bang Theory’ runs 10 meters to the couch, to play video games, in 3 seconds. Calculate Sheldon’s velocity.

Make your own problem with an Elbow partner and solve it.

Test  Graphing analysis  Lab conclusions  Difference between speed and velocity  Slope  GUESS Method  Apply GUESS method  Difference between mass and weight.  Bowling Ball observations