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## What similar action is involved in all of the following activities?

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**What similar action is involved in all of the following**activities? • You pedal a bicycle to start moving then apply the brakes to make it stop moving. • You hit the accelerator (gas pedal) to make a car speed up after the light turns green, then you hit the brakes to stop for the next red light. • A spring pushes a marble to accelerate it out of your launcher. • You push a baseball to speed it up for a throw. A friend then pushes on the ball after it enters her glove to slow it down and catch it. Newton’s 1st and 2nd Law 1**To hypothesize anything you must find patterns in data.**• To obtain the data you must conduct observation experiments • Like all experiments, this must have methods, analysis of assumptions, and analysis of error/uncertainty. Hypothesis… • Must be based on the pattern you devise from all data from all observation experiments. • Must use multiple representations and usually as variables in an equation (proportional relationship between physical quantities). Science Method Recap 2**Hypothesize how pushes and pulls change motion of different**masses. Materials (every single material MUST be used… this means you should design multiple experiments) • Mass scale • Your muscles (you lift things up and put them down… grarghhh!!!!!) • Big ball (bowling/medicine) *1kg=2.2046lbs on Earth* • Medium ball (tennis/baseball) • Small ball (marble) • Stopwatch • Meter stick Newton’s 1st and 2nd Law 3**Hypothesize how two things push or pull on each other.**Materials: 2 bathroom scales 2 spring scales 2 scooters Newton’s 3rd Law 4**Jackie exerts a 9.8 N force upward on a 1 kg snowball on**Earth. Draw this situation focusing on the snowball. Newton’s 3rd Law 5**Jackie exerts a 9.8 N force upward on a 1 kg snowball on**Earth. Draw this situation focusing on Jackie’s hand. Newton’s 3rd Law 6**Make a chart of representations for Newton’s Laws which**includes Math, Words, Diagram, and Example. Newton’s Laws 7**Make a diagram with force vectors for a box sitting**stationary on the ground. Force Diagrams 8**Make a force diagram for 3 stationary, stacked boxes. The**most massive box is on the bottom and the least is on the top. Use a separate diagram for each box as the system and one for all three as the system. Force Diagrams 9**Make a force diagram for a box being pushed on a rough**surface but remaining stationary. Force Diagrams 10**Make a diagram for a box being pushed along a rough floor at**a constant velocity. Force Diagrams 11**Make a diagram for 2 boxes (top 3kg, bottom 5 kg) stacked**vertically and being pushed horizontally along a rough floor at a constant velocity. Force Diagrams 12**A 2000 kg car sits on a 60o hill in San Francisco. What is**Fstaticfriction on car? Force Diagrams 13**Predict to test Newton’s Laws**Materials: phet.colorado.edu ‘Forces and Motion’**Hypothesize how friction operates on a subatomic**scale.Materials: phet.colorado.edu ‘Friction’**Hypothesize the relationship between the friction force of**the floor on your shoe and the amount of normal force exerted by the floor on your shoe. Friction Force 16**If a 3500kg object rests on a hill with a 37o slope and is**stationary, what is µstatic? Friction Force 17**If a 3500kg object slides on a 37o slope and is µkinetic =**0.004, what is this object’s motion? Friction Force 18**Hypothesize the relationship between the force used to**stretch a spring and the distance it is stretched. Spring Force 19**4 kg**µkinetic = 0.02 alarge = ? Assumptions? 12 kg Spring, Tension, and Friction Force 21**Hypothesize using the following materials:**String Pulleys Masses Balloons (Helium and Atmosphere) Springs Measuring Devices Scientific Method for Forces 22**Hypothesize a quantitative model for the force which moves**objects in circles. 1st Experiment: large ball, your feet2nd Experiment: ball on a string3rd Experiment: your body Central Force 23**When an object moves in a circle, what always changes about**its motion? What does not necessarily have to change? Does an object in circular motion at a constant speed have an acceleration? Why do you think so? Central Force 24**Annie spins a ball around her head on a string. The velocity**of the ball is 5 m/s, the ball has 1.3 kg of mass, and the radius of the circle she is spinning is 2m. Draw a diagram of this situation with all necessary physical quantities including the central force and acceleration.Then draw this same situation for:1) Doubled velocity2) Halved radius3) A ball 4 times larger***Make sure to create multiple representations and list assumptions.*** Central Force 25**We have now discovered how to reason the central**acceleration if we already know the central (centripetal) force.Do you think there is a way to measure the central acceleration directly without knowing the central force first?***Think of how we could measure linear acceleration and relate it to circular motion*** Central Force 26**It takes 34s for Shaun to do a full circle doughnut in a**snowy parking lot with his car. The lines in the snow from the car are 10m wide. What is the circular acceleration of car while it is doughnuting. Central Force 27**Mr. Mayes is swinging a bucket of water above his head. The**bucket and the water is 10kg. Mayes’ total wingspan is 78 inches and it takes him 2 seconds to spin the bucket. Create force diagrams for the top and the bottom of the motion. Central Force 28**Hypothesize the relationship between the quantities which**determine the gravitational force between two objects.Materials: phet.colorado.edu‘Gravity Force Lab’ Gravitational Force 29**msun = 1.989 x 1030 kgmearth = 5.97219 × 1024 kgG =**6.67384 × 10-11 m3 kg-1 s-2What is the gravitational force between Earth and Sol (the sun)? Gravitational Force 30**You are wearing a winter coat while riding on a subway. You**notice the strands on your jacket are being pulled toward the plastic seat on the subway car after rubbing around for a while. When you get up from the seat, you feel that the seat is pushing against the glass surface of your watch/phone/computer also.What in the name of all that is sweet and good is this skullduggery? Electric Force 31**Hypothesize the quantitative nature of the electric force**using all of the following:1. ‘Balloon and Static Charge’ phet2. Polarity shift game on The Universe and More3. Various rods, fur, wool, cloth Electric Force 32**Create a Venn diagram or chart comparing gravitational force**to electric force. Distance Forces 34