Monday, October 28, 2013 H Physics Standards: 1c Students know how to apply F=ma to solve one-dimensional motion problems that involve constant forces. Learning Objective: SWBAT design an experiment to test Newton’s 2 nd Law Agenda: 1.Warm Up 2.Review HW 3.Newton’s 2 nd Law Lab Homework Begin working on HW Problems Worksheet #F2: Due Wednesday Warm Up What is the net force on the box? 8N 3N 1N 4N

Tuesday, October 29, 2013 H Physics Warm Up If the cart from yesterday’s lab is pushed down by 3 N of force and it has a mass of.15 kg, how fast would it accelerate? Homework Worksheet #F2: Due Thursday Standards: 1c Students know how to apply F=ma to solve one-dimensional motion problems that involve constant forces. Learning Objective: SWBAT design an experiment to test Newton’s 2 nd Law Agenda: 1.Warm Up 2.Review Lab Day 1 3.Newton’s 2 nd Law Lab Continued

Wednesday, October 30, 2013 H Physics Warm Up If you want to prove that an object is accelerating, what data will you collect? What shape will your graph be? Homework Begin working on HW Problems Worksheet #F2: Due Friday Standards: Standards: 1c Students know how to apply F=ma to solve one- dimensional motion problems that involve constant forces. Learning Objective: SWBAT take 2 sets of data to show how acceleration is affected by changing mass. Agenda: 1.Warm Up 2.Turn in Part 1 of lab 3.Write a hypothesis for question 2 and 3 4.Collect Data For Part 2 & 3

Thursday, November 1, 2013 H Physics Homework Newton’s 2 nd Law #F2 Warm Up What is the weight in N, of a 25g object? Standards: 1c Students know how to apply F=ma to solve one-dimensional motion problems that involve constant forces. Learning Objective: SWBAT solve Newton’s 2 nd Law problems Agenda 1.Review Lab 2.Force Notes 3.Force Practice Problems

Friday, November 2, 2013 H Physics Homework #F2 & #FH3 due Monday Warm Up If an object’s mass is 20 kg, and it is being pushed with a Force of 100N, what will be the object’s acceleration? Standards: 1c Students know how to apply F=ma to solve one-dimensional motion problems that involve constant forces. Learning Objective: SWBAT reflect and discuss lab results and apply what they’ve learned to answer questions. Agenda: 1.Warm Up 2.Lab Report Review 3.Turn in Part 2 & 3 of Lab

Symbols, units and equations Study Guide --distance(d) and displacement (Δx or Δy ) units: meters (m) --speed (v s ), velocity (v) units: meters per second or kilometers per hour (m/s, or km/hr) --acceleration (a) units: meters per second squared or kilometers per hour squared (m/s 2, km/hr 2 ) --time or change in time (t or Δt) units: seconds Equations: Constant Velocity Constant Acceleration The Two equations of Motion The Two equations of Motion for Falling Objects a g =-9.8m/s 2 Forces

Profile of A Force Force is a vector (direction matters!) The Units of Force are Newtons (N) or it can also be written as kilograms times meters per second squared (kg*m/s 2) Equation: F net =MA o F net is the result of adding all o of the forces together.

Types of Forces From your book p. 94 Table 4-2 ForceSymbolDefinitionDirection FrictionFfFf Resistive Force. Comes from rubbing against or sliding across surfaces. Parallel to the surface and opposite the direction of sliding NormalFNFN The force exerted on an object by the ground, a table, a platform, or any surface. Perpendicular to and away from the surface. SpringF sp Restoring Force. The push or pull a spring exerts on an object. Opposite the displacements of the object at the end of the spring. TensionFTFT The pull exerted by a string, rope, or cable when attached to something. Away from the object and parallel to the string, rope, or cable at the pont of attachment. ThrustF thrust,FapA general term for the forces that move objects such as rockets, planes, cars and people. In the same direction as the acceleration of the object. WeightFgFg Attractive Force of two objects due to gravity. Usually Earth and and object Straight down towards the center of the earth. Air Resistance/DragF AR Resistive Force, comes from air/wind hitting moving objects Opposite of Motion

Calculating Net Force 1.5 N West, 3 N West F net =? 2.15 N West, 10 N East, 7 N West F net =? 3.2 N West, 1 N East, 7 N West, 8 N East F net =? 4.4 N North, 4 N South, F net =? 5.6 N North, 2 N West, 4N East, 7 N South F net =? #F1a Force each of the following draw a diagram for each and solve.

#F1b

Carts & Masses Engage - You will construct gliders to be launched from a catapult at the end of the unit but not yet–at this point in time, Today, you are going to design an experiment to determine what happens to an object when there’s a net force acting on it. Explore - Students are shown the experimental setup (Figure 4). Respond following questions, and provide an explanation for your thoughts: o What will happen to the cart when there is a force applied to it? o What if the applied force is increased? What about the cart’s motion will change? o What if the cart’s own mass is increased? How will its motion change? Test - Design and execute experiments to test your hypothesis from the explore section (at least 5 trials for each hypothesis). Explain – Make a graph for each set of data. You decide what you think you should graph. Elaborate Class Discussion Questions Why is it a good idea to do multiple trials? o “What aspects” changed from one trial to the next? o What variable did you change on purpose? o What variable changed as an effect of changing your independent variable? Newton’s 2 nd Law Questions: o What happens if we apply a net force on an object? o What happens if that net force is increased? o What happens if the mass of the object itself increases? We have a mathematical expression for this: F net = ma. Evaluate Complete HW #F2 Figure 4. Experimental setup for cart & mass activity

Cart and Masses Lab Instructions Part 1 Due Today o Use Δx=(1/2)at 2 to find the average acceleration o Use your x vs t graph to prove the object is accelerating Part 2 Due Thursday All data must be collected IN CLASS Use F net =ma to find the acceleration. Compare this to the average acceleration you can calculate from Δx=(1/2)at 2. Explain the differences Graph F net vs m and use this graph to prove your hypothesis Part 3 Due Thursday All data must be collected IN CLASS Use F net =ma to find the acceleration. Compare this to the average acceleration you can calculate from Δx=(1/2)at 2. Explain the differences. Graph F net vs m and use this graph to prove your hypothesis. EVERY PERSON WILL TURN IN THE FOLLOWING

Newton’s 2 nd Law Problems 1. If a student accelerates on his/her bicycle at 4m/s 2, and the student has a mass of 77 kg. How much force does s/he apply to the bicycle? 2. Find the weight of the following people: Rickey is 100 kg, Manny is 150kg, and Donna is 65kg and the acceleration due to gravity is 9.8m/s 2. 3 How much force does a baseball experience if the baseball bat accelerates the ball at 8m/s 2 and the mass of the baseball is 5kg? 4. How much force would a 10kg baseball experience if the bat accelerated the ball at 20m/s 2 ? 5. What is the mass of a bullet that accelerates at 100m/s 2 by a 12 N Force when shot out of a gun? 6a. Thrust from a rocket’s engine equal to 100,000 N launches a shuttle with a mass of 10,000 kg into the air. What is the rockets acceleration? 6b*If the acceleration due to gravity is 9.8 m/s 2 will the rocket be able to escape the earths atmosphere? 7. A wide receiver (90 kg) is tackled after catching a football by one of the safeties (99 kg). The safety applies a force of 250N? How fast did the receiver decelerate? (Be careful when you choose which mass to use.) #F2

Newton’s 2 nd Law 2 #FH3 1.What does F net mean? 2.What is the equation Newton’s 2 nd Law. 3.What do you change from Newton’s 2 nd Law equation in order to find weight (W or F g) ? 4.Find the net force of mini car racing if friction is 20N, the accelerator supplies 50N, and air resistance is slowing it down by 2N. 5.If the car from problem 4 has a mass of 1 kg, what is the car’s acceleration? 6.Which direction does Gravitational Force push? 7.Describe the Normal Force? 8.Friction acts in which direction? 9.If an object is flying northeast, which direction is air resistance pushing? 10.Find the mass of an object if it accelerates at 2 m/s 2, when 20N of Force pushes it. 11.Find the mass of an object if it accelerates at 2 m/s 2, when there is an applied force of 80 N, a force of friction of 20N, and air resistance of 10N. 12.Find the applied Force if a 20kg object is accelerated at 10m/s 2 and friction is opposing the motion with 30N of Force.