Pre-Lab 6A: Newton’s First and Second Laws http://www. youtube

All lab write-ups must be in YOUR OWN WORDS Yes, you should discuss the lab and results w/ your partner, but using another person’s wording/answers is CHEATING and ALL parties involved will get a ZERO for each question/answer. This is no joke: copying = cheating = zero

Purpose The relationships between force and motion are known as Newton’s laws. The First Law explains what happens when there is NO net force on an object, and the Second Law explains what happens when there IS a net force. The two laws are closely related. We will focus in this investigation on what happens to the Energy Car’s motion when you change the force and the mass separately. Both laws apply!

Background Define: Newton’s first law of motion Inertia Provide the formula for the second law of motion CALCULATORS: EVERY BODY DOES THEIR OWN CALCULATIONS, WHY????

Drawing

Key Question What is the relationship between force and motion?

Section 1: For this first part of the investigation you will use different amounts of force (change the # of rubber bands) to launch the car. you will measure the RESULT of the force and calculate the speed caused by the force of the rubber band. Make a formal hypothesis: What will happen to the speed of the car as the force gets larger? use the “if…then…because” format.

Section 2: Put one photogate on the first square mark after the rubber band. Put one marble in the center of the car. Car faces what direction: look at drawing? Use the screw to launch the car using the same deflection of the rubber band each time. What is the deflection # in cm (drawing)? This means the same force is applied to each launch; do this 3 times for each of the rubber bands: calculate average: You’ll be doing 9 launches, recording the 3 averages all your launches have to have a precision of 0.0015 seconds (not their times!!!!) Repeat the experiment with two and three rubber bands.

What is the formula for speed? NOW: Read line 5 (section 2) to determine the distance used Section 3: Make a change in FORCE graph showing how the speed of the car on the y-axis and the number of rubber bands on the x-axis Notice letter b also has a question which needs an answer Make your graph before doing section 4

Section 4: launch cars with only one rubber band and four different masses. Measure the mass (how/resolution?) of the car with 0, 1, 2, and 3 steel marbles.

Section 5: Use Table 2 to make a change in MASS graph: the speed of the car (y) against the mass (x).

Section 6 (required): You will first launch the car with one rubber band and no marbles. Then you will launch the car with TWO rubber bands and TWO marbles in the car. This means you will double both the force and the mass at the same time. How do you think these times compare? Make a formal hypothesis/prediction: use the “if…then…because” format. Test your hypothesis END

Post Lab 6A: Newton’s First and Second Laws

Purpose The relationships between force and motion are known as Newton’s laws. The First Law explains what happens when there is NO net force on an object, and the Second Law explains what happens when there IS a net force. The two laws are closely related. We will focus in this investigation on what happens to the Energy Car’s motion when you change the force and the mass separately. Both laws apply!

Key Question What is the relationship between force and motion?

Background Define: Newton’s first law of motion Inertia Provide the formula for the second law of motion

Section 1/2: What was your hypothesis: if you increase the force (# rubber bands) acting on a car then the speed did what and why? What were your results: graph: axis, data line: direction/shape/relationship? What part of the motion is the rubber band affecting SPEED?

Section 4/5: What would you hypothesize: if you hold constant the force (# of rubber bands) acting on a car but you increase the mass of the car then what happened and why? Graph: axis, data line: direction, description/relationship? How does Newton’s first law explain your results? Support your theory: does force cause speed or does it cause a change in acceleration (which comes first: the chicken or the egg?) ?

Section 6: If you double the force and double the mass, what can you expect as an outcome for the motion? Show how Newton’s second law helps explain this: F = M x A  ? A = 2F 2M