(UNIT I) Measuring Activity Name

Transcription

1 (UNIT I) Measuring Activity Name Purpose: To become more familiar with the metric system (SI) of measurement. Make estimates first and then measure it. Pre Lab reading: Write all units!! Station Measure Estimate Measured Value 1 Length of room (m) 2 Height of room (m) Height of room (yds) 3 Your height (cm) Your height (inches) 4 Diameter of your pen (mm) Diameter of your pen (inches) 5 Mass of penny (grams) Thickness of penny (mm) Thickness of penny (cm) 6 Length of your arm (cm) Length of your arm (inches) 7 8 Gallons of water in milk jug Liters of water in milk jug Weight of barbell weight (pounds) Mass of barbell weight (kg) 9 You or your teacher s weight in pounds You or your teacher s mass in kg (calculate based on data from 8) 10 Weight of bottle of sand (in Newtons) Llist the metric base units for the following (your book might be helpful for this) Length Volume Mass Force Time 1

2 Speed Lab Name: Directions: Find the speed of 4 different objects. Show all units, formula(s) and calculations. Text reference: Chapter 2 1) What two bits of information will you need to calculate the speed of a object? 2) What formula will you use to calculate speed? 3) When collecting data for each object, why is it important to do multiple trials? Data: Create a data table below for each object you test. Indicate # of trials. Label columns and rows, show units. If you need more room use back of sheet. Post lab Questions: 4) What problems did you encounter in finding the speed of the objects (there were some!)? 5) Were you finding instantaneous speed or average speed? Explain the difference: 6) How is velocity different than speed? 7) Give an example of how an object could have a constant speed but not a constant velocity. 2

3 Acceleration Causing Mass Elation Lab Name: Purpose: To calculate the acceleration of a marble coasting down a ramp. Materials: 1 grooved ruler, 1 marble, 1 stop watch, 1 meter stick, piece of masking tape Procedures Part I: 1) Place the grooved ruler on one book to make an inclined ramp. 2) Measure and mark a distance of 1 meter from the bottom of the ramp. 3) Place the marble on the track and allow it to roll down the ramp. 4) Measure the time taken for the marble to travel from the beginning mark to the ending mark and record. 5) Repeat steps 3 and 4 a total of 5 times. Record the data in the data table. 6) Calculate the speed for each trial (See your speed lab if you need help). Record this answer in the data table. Trial number # of book(s) Horizontal distance traveled 1 1 1m 2 1 1m 3 1 1m 4 1 1m 5 1 1m Time (s) marble rolls through 1m Horizontal speed Average Speed of trials: (this will be V final ) 7) Calculate and record the average speed for all 5 trials: 8) Determine the time it took for the marble to roll down the ramp. To do this, roll the marble down the ramp a few times and clock how much time it takes for it to roll from top of ramp to bottom. Then take the average. Show all work below. Ave. time for marble to roll down the ramp = sec. Part II: Repeat part I but this time use 3 books under the grooved ruler. Trial number # of book(s) Horizontal distance traveled 1 3 1m 2 3 1m 3 3 1m 4 3 1m 5 3 1m Time (s) marble rolls through 1m Horizontal speed Average Speed of 5 trials: (this will be V final ) 9) Determine the time it took for the marble to roll down the ramp. To do this, roll the marble down the ramp a few times and clock how much time it takes for it to roll from top of ramp to bottom. Then take the average. Show all work below. Ave. time for marble to roll down the ramp = sec. 3

4 Calculations: a) Write the formula for acceleration: b) Let s assume that the average horizontal speed (the speed at the bottom of the ramp) is about the same speed the marble has at the moment it reaches the bottom of the ramp. Based on the above assumption, calculate the acceleration of the marble down the ramp when there was only 1 book under the ramp. Show formula, work, and units: c) Based on the above assumption, calculate the acceleration of the marble down the ramp when there was 3 books under the ramp. Show formula, work, and units: Word bank for letters d, e, f (only 3 words are used): constant, friction, gravity, acceleration, d) What force was causing the marble to accelerate down ramp? e) When the marble was rolling across the flat table top, we said was very small and the marble moved at an almost speed. f) In all actuality, was the marble accelerating when it was rolling on the flat table? (this one is a little tricky, hint: remember acceleration is any change in velocity over time.) Yes or No Explain: g) Suppose a car moving in a straight line steadily increases its speed each second. If the car went from 0 m/s to 40 m/s in 4 seconds, what would its acceleration be? (see section 2.4 in book) 4

5 Name Walk This Way, Talk this Way 1) Make a T chart below each person. Collect data for the following people (include time and position at every 10 m interval). A: Constant Walker B: Constant jogger C) Accelerator D) Decelerator E: constant walk 50 m For 50 For 50 m For 50 m for 50 m jog back to the -10m Make a graph showing displacement (on the y axis) vs. time (x axis). Include a title, labels, & units 5

6 2) Displacement is a measure of change in position or location. x 1=> initial postion, x 2 => second position Use the data for person D (walker/return jogger) and complete the data table below: Useful formulas: displacement = x 2 x 1 displacement (m) x 1 x 2 0 to 10 m = 10 m 10 to 20 m = 10 m 20 to 30 m = 10 m 30 to 40 m = 40 to 50 m = 50 to 40 m = 40 to 30 m = 30 to 20 m = 20 to 10 m = 10 to 0 m = 0 to -10 m = t => time change each 10 m displacement (in seconds) velocity ave. = displacement / time change V ave. => average velocity (m/s) Accumulated time (sec) (same as on t-chart your recorded on previous page) 3) Looking at the data chart above, what factor determines if the person had a positive velocity or a negative velocity? 4) Graph the velocity ave.(on the y axis) vs. accumulated time (on the x axis) below. Include Title, label, units. Take into account you will have to graph some negative velocity values hint: run the x axis (for time) across the middle of the grid below 6

7 Sonic Ranger Match the Graph Name I) Have each person in your group match at least 1 d vs t graph. Sketch 3 of the graphs your group members came across in the space below. Label each section of the graph with a letter. Show units for x & y axis. Graph 1: Graph 2: Graph 3: II) For each graph above, describe how you would have to walk to match that graph. Your description should include: 1) your direction of motion relative to the ranger (towards or away from the ranger) 2) Your relative speed of motion (slow, medium, fast) 3) If your speed was at a constant rate or if you slowed down or increased your speed at any point.) Description For graph 1: 1) relative directions: 2) relative speeds: 3) relative rate of speed: Description For graph 2 1) relative directions: 2) relative speeds: 3) relative rate of speed: Description For graph 3 1) relative directions: 2) relative speeds: 3) relative rate of speed: Continued next page >>>>>>>>>>>>>>>>>> 7

8 B.) Select VEL MATCH under APPLICATIONS: III) Have each person in your group match at least 1 v vs t graph. (WARNING: this is tough to match!) Sketch 2 of the graphs your group members came across in the space below. Label each section of the graph with a letter. Show units for x & y axis. Graph 1: Graph 2: Graph 3: IV) For each graph above, describe how you would have to walk to match that graph. Your description should include: 1) your direction of motion relative to the wall (towards or away from the wall) 2) Your relative speed of motion (slow, medium, fast) 3) If your speed was at a constant rate or if you slowed down or increased your speed at any point.) Description For graph 1: 1) relative directions: 2) relative speeds: 3) relative rate of speed: Description For graph 2: 1) relative directions: 2) relative speeds: 3) relative rate of speed: Description For graph 3: 1) relative directions: 2) relative speeds: 3) relative rate of speed: 8

9 Cause I m Free, Free Fallin Name Goal: The purpose of this lab is to show you two practical uses of the constant acceleration formulas. Using the equations you will determine how fast and how high you can throw a ball. Materials: Stopwatch, ball, your formula chart, and lots of space. Directions: 1. You should try and throw the ball as high as possible. 2. The only data you need is the time the ball is in the air. (Measure the time it takes for the ball to reach the original height you threw it at.) 3. Do three trials and take the average. Data: Trial #1 Trial #2 Trial #3 Average Analysis: 1. The magnitude of acceleration due to gravity (g) is. Which direction does gravity cause objects to accelerate? If an object is thrown in the air, and we ignore air resistance, what force(s) are acting on the object? 2. We know from our activity that the time going up equals the time going down ( t up = t down). Calculate t up and t down: 3. Find out how fast (the speed) you threw the ball initially. SHOW YOUR WORK!!! 4. At the peak, what was the ball s speed? 5. At the peak, what was the ball s acceleration? (Be careful!) 6. Now figure out how high you threw the ball. SHOW YOUR WORK!!! (What value for t did you use?) 7. Now let s talk about the way down. So we are starting at the top and going to where you threw the ball from. What will the initial speed (or velocity) be this time? 9

10 8. Calculate the speed that the ball would have after it returns to the original height you threw it from. (Be sure to use t down). SHOW YOUR WORK!!! 9. What do you notice about the answers you got for q. 3 and question 8? 10. Fill in the chart below according to your results. Time (seconds) Height (d) (meters) Speed (m/s) Acceleration (m/s)² A: B: C: 11) Sketch figure 2.6 (p 18) from your book and explain how speeds compare at equal heights on the ball s trajectory (path). 10

11 Hangin Around (Be Like Mike) Goal: To determine your hang time without using a stopwatch. Name Directions: 1. Stand next to a wall with your arm extended and place a piece of tape as high up the wall as you can without jumping. 2. Jump as high as you can and place a piece of tape at this highest point (on the wall of course). 3. Measure the distance between the pieces of tape in meters. (If you can measure in inches you can convert to cm and then meters using the following conversion factor; 1 inch = 2.54 cm). This distance is how high you can jump vertically. Vertical jump = m 4. What is he formula that you use to determine distance for something that s free falling? (Remember you are free falling after you reach the peak of your jump.) 5. Rearrange the fomula above so that you can find the time it takes something to fall a given distance. 6. Use the formula in 5 to determine how long it takes (time) to go from the peak to the ground. 7. Because we know that the time up equals the time down, double the time in #6 to find your hang time. 8. People always talk about how Michael Jordan flies through the air. Take a guess of what Michael Jordan s hang time is. (You do NOT have to do any calculations.) 9. Well Michael Jordan has a vertical leap of 48 inches (1.22 meters) so determine what his true hang time is. SHOW ALL WORK! INCLUDE FORMULAS! 10.) You can compare your reaction time with that of a friend by catching a ruler that is dropped between your fingers. Snap your fingers shut as soon as you see the ruler released. The length of ruler that passes through your fingers depends on your reaction time. You can find your reaction time in seconds by using the equation: d=½gt². The first step is to rearrange the equation solving for time: t = Now plug in the distance (in meters) that passed through your fingers and calculate. 11) Now try this: Hold a dollar bill (or other denomination) vertically so that the midpoint hangs between a friends fingers that are apart. Challenge your friend to catch it by snapping their fingers shut when the bill is released. Explain why if this is done properly, the bill won t be caught. (see reaction time activity on p. 21) 11

12 Graph Sketching and Recognition W.S. Go to the web site: Use the following graph to answer Questions #1 - #7. 1. Which object(s) is(are) maintaining a state of motion (i.e., maintaining a constant velocity)? 2. Which object(s) is(are) accelerating? 3. Which object(s) is(are) not moving? 4. Which object(s) change(s) its direction? 5. On average, which object is traveling fastest? 6. On average, which moving object is traveling slowest? 7. Which object has the greatest acceleration? Use the following graph to answer Questions #8 - # Which object(s) is(are) maintaining its state of motion? 9. Which object(s) is(are) accelerating? 10. Which object(s) is(are) not moving? 11. Which object(s) change(s) its direction? 12. Which accelerating object has the smallest acceleration? 13. Which object has the greatest velocity? 12

13 Label all axis in sketches. 14. Sketch a position-time graph for an object which is moving with a constant, positive velocity. 15. Sketch a position-time graph for an object which is moving with a constant, negative velocity. 16. Sketch a position-time graph for an object moving in the + dir'n and accelerating from a low velocity to a high velocity. 17. Sketch a position-time graph for an object moving in the + dir'n and accelerating from a high velocity to a low velocity. 18. Sketch a position-time graph for an object moving in the - dir'n and accelerating from a high velocity to a low velocity. 19. Sketch a position-time graph for an object moving in the - dir'n and accelerating from a low velocity to a high velocity. 20. Sketch a position-time graph for an object moving in the + dir'n with constant speed; first a slow constant speed and then a fast constant speed. 21. Sketch a position-time graph for an object moving in the + dir'n with constant speed; first a fast constant speed and then a slow constant speed. 22. Sketch a position-time graph for an object moving in the - dir'n with constant speed; first a slow constant speed and then a fast constant speed. 23. Sketch a position-time graph for an object moving in the - dir'n with constant speed; first a fast constant speed and then a slow constant speed. 24. Sketch a position-time graph for an object which moves in the + direction at a slow constant speed and then in a - direction at a fast constant speed. 25. Sketch a position-time graph for an object which moves in the + direction at a fast constant speed and then in a - direction at a slow constant speed. 26. Sketch a position-time graph for an object which moves in the direction at a slow constant speed and then in a + direction at a fast constant speed. 27. Sketch a velocity-time graph for an object moving with a constant speed in the positive direction. 13

14 28. Sketch a velocity-time graph for an object moving with a constant speed in the negative direction. 29. Sketch a velocity-time graph for an object which is at rest. 30. Sketch a velocity-time graph for an object moving in the + direction, accelerating from a slow speed to a fast speed. 31. Sketch a velocity-time graph for an object moving in the + direction, accelerating from a fast speed to a slow speed. 32. Sketch a velocity-time graph for an object moving in the - direction, accelerating from a slow speed to a fast speed. 33. Sketch a velocity-time graph for an object moving in the - direction, accelerating from a fast speed to a slow speed. 34. Sketch a velocity-time graph for an object which first moves with a slow, constant speed in the + direction, and then with a fast constant speed in the + direction. 35. Sketch a velocity-time graph for an object which first moves with a fast, constant speed in the + direction, and then with a slow constant speed in the + direction. 36. Sketch a velocity-time graph for an object which first moves with a constant speed in the + direction, and then moves with a positive acceleration. 37. Sketch a velocity-time graph for an object which first moves with a constant speed in the + direction, and then moves with a negative acceleration. 14

15 Move it or Lose it Lab PROCEDURE Given the following graphs, sketch the other two along with a brief description of the object's motion. **Remember with sonic ranger + direction is moving away from it, - direction is moving towards it. Directions: In the table below, use motion detector to fill in the missing P vs t or V vs t graph. In the 4 th (last) column, describe the motion needed to match the graph for each row (example: constant speed in - direction, stop, and move with increasing speed in + direction) Leave this column blank p vs. t v vs. t Description of motion until class consensus

16 LAB 1.5 CRASHING CARS PURPOSE PROCEDURE Name Hour Date To calculate the starting distance of two cars so they collide at a given position. Each group will be given a car, your group s car must collide with the teacher s car at a point given by your instructor. The teacher s car must be at least 50 cm from the collision point, and both cars must begin at the same time. You must clearly show how you 1) measured the speed of both of the cars and 2) the calculated the starting points for each car. It should be written so that you could hand it to a senior who has taken physics and they could understand the work. Show work below: To measure the speed of the cars we: Group s car: Teacher s car: To calculate the starting points we: E.C. (IF time allows), Redo the starting point calculations, but this time calculate the starting points for the two cars if the time of release of one the cars is 2 seconds after the other car. Show work and call over Teacher when done 16

17 Unit Notes/Video q s: Bill Nye Gravity Video Questions 1. When the bowling ball and apple were dropped, what happened? 2. What happened when the astronaut dropped the feather and hammer on the moon? Why? 3. What are the 4 forces that act on an airplane at take off? 4. On Earth, gravity always pulls us. Bonus: describe an error in the video 17

18 Unit 1 practice Test 2015 Measuring Activity Q s 1) An offensive lineman weighs 330 pounds. What is his mass in kg? 2) Which is closest to the length of the physics classroom room in meters? a) m b) 1.50 m c) 12 m d) 17 m e) 23 m 3) How many mm in a meter? How many cm in a meter? Speed Lab: 4) A toy car travels 2 m in 4 seconds. What is its average speed in m/s? 5) The speedometer on a car indicates: a) instantaneous speed b) average speed 6) I f you drive at a constant speed on a curved road is your velocity constant? Acceleration Lab: 7) Let s suppose a marble rolls down a ramp 0.30 m long that is on top of a table. At the bottom of the ramp, the marble continues to roll through a distance of 1.0 m on a horizontal, smooth, table top. If the time it takes for the marble to roll though the 1.0 m horizontal distance is 3.0 seconds, what is the average horizontal speed? (ignore effects of friction). 8) What is the acceleration of a marble rolling down a ramp? givens: length of time to roll down the ramp from rest: 0.40 seconds, initial (starting) speed = 0 m/s, marble speed at bottom of the ramp: 1.4 m/s 9) Which has more acceleration a wolf increasing its speed from 0 to 8 m/s in 2 seconds or a coyote increasing its speed from 0 to 15 m/s in 5 seconds? Walk this Way Activity, Graph Sketching and Recognition, Sonic Ranger LAb: Position vs. time: 10-. Which part above shows acceleration? Which part shows an object that is moving at a constant speed? Which shows and object not moving? q s apply to graph to the right 11.) Which object(s) above is(are) accelerating - going from a low speed to a high speed? 12) Which object(s) above is (are) not moving? 13) Which objects change directions? 14) Which objects move at a constant speed? 18

19 The position vs. time graph below applies to question 15 15) Which object(s) are moving from a high speed to a low speed (they slow down)? graph for q s According to the Sonic ranger graph example below, describe the motion of the person during the last segment of their graph plot. (assume toward detector is direction and moving away from the detector is + directon): Position vs. Time: 16) Describe the motion of the person at the 1 st segment of their graph plot (when it slopes upward): 17) Describe the motion of the person at the 2 nd segment of plot. (when it is flat): 18) Describe the motion of the person during the last segment of their graph plot (when it slopes downward). Q s apply to graph - > 19) Which object(s) have constant velocity the entire time? 20 Which object(s) change(s) its direction? 21 Which object(s) never move during the entire time plotted? 22) Which object(s) accelerate at least some of the time? 19

20 For 23-25) Examime the Sonic ranger graph example below, (Assume towards the motion detector is direction and moving away from the detector is + direction): Velocity vs. Time *careful! This is a velocity vs. time graph!!: 23) Describe the motion of the person at the very end of their graph plot (when it is below the zero line): a) Walking at a constant speed towards detector c) accelerating towards the detector b) Walking at a constant speed away from detector d) accelerating away from the detector e) no motion 24) Describe the motion of the person at the very beginning of their graph plot (when it slopes upward): a) Walking at a constant speed towards detector c) accelerating towards the detector b) Walking at a constant speed away from detector d) accelerating away from the detector e) no motion 25) Describe the motion of the person at the 2 nd segment of plot. (when it is flat) a) Walking at a constant speed towards detector c) accelerating towards the detector b)walking at a constant speed away from detector d) accelerating away from the detector e) no motion Hanging Around Be like Mike Activity (Ignore Air Resistance) : 26) a) When you jump up, what is your velocity at the peak of your jump? b)what is your acceleration? 27) Suppose you jumped 0.40 meter vertically How much time would it take you to fall from the peak to the ground? 28) What would be your total hang time for question 31? 29) A friend challenges you to a reaction time test. She drops a meter stick and you catch it as fast as you can with your fingers. The best you could is to catch the meter stick after it fell 20 cm. What is your reaction time? (Remember to convert to cm to meters) Cause I m Free, Free Falling Lab (Tennis ball Throw lab ): (Ignore Air Resistance): 30) Suppose you throw a ball straight up and it takes 3 seconds for it to go up and come back down to its initial launch height(total time = 3.0 sec). Let s look at the way up. How much time did it take for the ball to go from the initial height to the peak? 31) How fast did you throw the ball initially? 32) What was the ball s vertical velocity at the peak of its flight? 33) What was the magnitude (size) of the ball s acceleration at the peak of its flight? 34) What was the maximum height the tennis ball reached? 35)What is the speed of the ball upon return to its original launch height?. 20