Presentation on theme: "December 14 Physics. A train car (mass=1000 kg) rear ends a stationary boxcar (mass = 5000 kg). After the collision they stick together and move at 5."— Presentation transcript:
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?
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
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
Calculate: Obtain a numerical answer showing the relevant stages in the working.
Calculate the velocity of the dart before collision Before crash After (Dart )v d =(dart + car)v
Examine: Consider the lab in a way that uncovers the assumptions and interrelationships of the lab.
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?)
Justify: Give valid reasons or evidence to support your answer.
Justify the answer Show how your answer makes sense Is the answer realistic? Why, why not? How could you tell?
Evaluate: Assess the implications and limitations; make judgments about the ideas, works, solutions or methods in the lab.
Evaluate: Assess the limitations of the lab, and make judgments. useful features of lab Limitations of lab Is this lab valuable to do?
Suggest: Propose a solution, hypothesis or other possible answer.
Suggest better: Procedure Equipment Measurement Etc.
Out: Suggest a whole new lab that would address the same concept: