1. December 14 Physics

2. A train car (mass=1000 kg) rear ends a stationary boxcar (mass = 5000 kg). After the collision they stick together and move at 5 m/s. What was the velocity of the 1000 kg train car before?

3. Objective: To analyze our dart lab data. Success criteria: Calculate the velocity of the dart before collision Examine the data for precision Justify the answer Evaluate the lab for possible errors Suggest improvements to the lab

4. Lab: Tailgated by a dart

5. Tail gated by a dart Problem: what is the velocity of the dart before it hits the car? Hypothesis: I believe that the dart goes ----- m/s before it hits the car. Procedure: sketch a diagram Data table: –Mass of car –Mass of dart –Velocity of car + dart after

6. Calculate: Obtain a numerical answer showing the relevant stages in the working.

7. Calculate the velocity of the dart before collision Before crash After (Dart )v d =(dart + car)v

8. Examine: Consider the lab in a way that uncovers the assumptions and interrelationships of the lab.

9. Examine the data for precision (Max – Min) / 2 x 100 Average Examine the lab for assumptions Examine the lab for interconnections (what depends on what?)

10. Justify: Give valid reasons or evidence to support your answer.

11. Justify the answer Show how your answer makes sense Is the answer realistic? Why, why not? How could you tell?

12. Evaluate: Assess the implications and limitations; make judgments about the ideas, works, solutions or methods in the lab.

13. Evaluate: Assess the limitations of the lab, and make judgments. useful features of lab Limitations of lab Is this lab valuable to do?

14. Suggest: Propose a solution, hypothesis or other possible answer.

15. Suggest better: Procedure Equipment Measurement Etc.

16. Out: Suggest a whole new lab that would address the same concept: