Monday, October 28, 2013 Physics

1. Warm Up What is the net force on the box? Monday, October 28, 2013 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 2nd Law Agenda: Warm Up Review HW Newton’s 2nd Law Lab 1N 8N 3N 4N Homework Begin working on HW Problems Worksheet #F2: Due Wednesday

2. 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? Tuesday, October 29, 2013 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 2nd Law Agenda: Warm Up Review Lab Day 1 Newton’s 2nd Law Lab Continued Homework Begin working on HW Problems Worksheet #F2: Due Wednesday

3. Wednesday, October 30, 2013Physics 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: Warm Up Turn in Part 1 of lab Write a hypothesis for question 2 and 3 Collect Data For Part 2 & 3 Homework Problems Worksheet #F2: Due Friday Warm Up If you want to prove that an object is accelerating, what data will you collect? What shape will your graph be?

4. Thursday, October 31, 2013 Physics Standards: Standards: Standards: 1c Students know how to apply F=ma to solve one-dimensional motion problems that involve constant forces. Learning Objective: SWBAT create an experiment testing the effect of mass on acceleration. Homework Cart & Masses Lab Part 3 Agenda Review Part 2 Lab Part 3 Cart & Masses Lab Warm Up What is the weight in N, of a 25g object? Remember to change g-> kg 1000g=1kg

5. 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? Friday, November 1, 2013 Physics 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: Warm Up Lab Report Review Turn in Part 2 & 3 of Lab Agenda: Warm Up Homework #F2 & #F3

6. Symbols, units and equations Study Guide --distance(d) and displacement (Δx or Δy) units: meters (m) --speed (vs), 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/s2, km/hr2) --time or change in time (t or Δt) units: seconds Equations: Constant Velocity Constant Acceleration Forces The Two equations of Motion The Two equations of Motion for Falling Objects 1. ag=-9.8m/s2 2.

7. 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/s2) • Equation: Fnet=MA • Fnet is the result of adding all • of the forces together.

8. Types of Forces • From your book p. 94 Table 4-2

9. Balancing Forces N W E S • We know that if Forces are balanced or non-existent, an object will travel at constant speed or at rest. • If they are imbalanced, they will go in the direction of the Net Force or Total Force in one direction. • Net Force means: add up all of the Forces. • Force is a vector (direction matters, so) add the following forces. 4N 5N 7N

10. Calculating Net Force #F1a Force each of the following draw a diagram for each and solve. • 5 N West, 3 N West Fnet=? • 15 N West, 10 N East, 7 N West Fnet=? • 2 N West, 1 N East, 7 N West, 8 N East Fnet=? • 4 N North, 4 N South, Fnet=? • 6 N North, 2 N West, 4N East, 7 N South Fnet=?

11. F1b

12. Carts & Masses Figure 4. Experimental setup for cart & mass activity 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: • What will happen to the cart when there is a force applied to it? • What if the applied force is increased? What about the cart’s motion will change? • 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? • “What aspects” changed from one trial to the next? • What variable did you change on purpose? • What variable changed as an effect of changing your independent variable? Newton’s 2nd Law Questions: • What happens if we apply a net force on an object? • What happens if that net force is increased? • What happens if the mass of the object itself increases? We have a mathematical expression for this: Fnet = ma. Evaluate Complete HW #F2

13. Newton’s 2nd Law Problems #F2 • 1. If a student accelerates on his/her bicycle at 4m/s2, 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/s2. • 3 How much force does a baseball experience if the baseball bat accelerates the ball at 8m/s2and the mass of the baseball is 5kg? • 4. How much force would a 10kg baseball experience if the bat accelerated the ball at 20m/s2? • 5. What is the mass of a bullet that accelerates at 100m/s2by 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/s2 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.)

14. Cart and Masses Lab Instructions EVERY PERSON WILL TURN IN THE FOLLOWING • Part 1 Due Today • Use Δx=(1/2)at2 to find the average acceleration • Use your x vs t graph to prove the object is accelerating • Part 2 Due Thursday • All data must be collected IN CLASS • Use Fnet=ma to find the acceleration. Compare this to the average acceleration you can calculate from Δx=(1/2)at2. Explain the differences • Graph Fnetvsm and use this graph to prove your hypothesis • Part 3Due Thursday • All data must be collected IN CLASS • Use Fnet=ma to find the acceleration. Compare this to the average acceleration you can calculate from Δx=(1/2)at2. Explain the differences. • Graph Fnetvsm and use this graph to prove your hypothesis.

15. Newton’s 2nd Law 2 #F3 • What does Fnetmean? • What is the equation Newton’s 2nd Law. • What do you change from Newton’s 2nd Law equation in order to find weight (W or Fg) ? • 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. • If the car from problem 4 has a mass of 1 kg, what is the car’s acceleration? • Which direction does Gravitational Force push? • Describe the Normal Force? • Friction acts in which direction? • If an object is flying northeast, which direction is air resistance pushing? • Find the mass of an object if it accelerates at 2 m/s2, when 20N of Force pushes it.