Unit 5: Force and Motion Week 2 10/26/15 – 10/30/15

Learning Targets Monday, October 26, 2015 I can identify a force. I can demonstrate forces acting on an object. I can demonstrate how unbalanced forces change the direction of an object’s motion. I can calculate the net force. Warm Up Complete the Before column of your Force and Motion Anticipation Guide. Circle whether you agree or disagree with the statement.

Tug of War Illustrate the game we just played in your notebook and discuss the following questions with a partner. Which direction did the winning team pull the rope? Should we use a large arrow or a small arrow to indicate the winning team’s direction? What size arrow should we use to indicate the losing team’s direction? Why is it appropriate to use a large arrow to represent the winning team? What does the arrow mean? What does a force cause to happen? Do you agree or disagree with the following statement? Why or why not? The forces in the game of tug of war were balanced. Which direction did the winning team pull the rope? Students should be able to indicate right or left. Should we use a large arrow or a small arrow to indicate the winning team’s direction? The winning team should use a large arrow to indicate their direction. What size arrow should we use to indicate the losing team’s direction? The losing team should use a small arrow to indicate their direction. Why is it appropriate to use a large arrow to represent the winning team? What does the arrow mean? The arrow represents the direction and amount of the force, and the winning team had more force. Therefore, a large arrow would be appropriate representation. What is a force? A force is a push or pull. What does a force cause to happen? A force can cause motion to start, stop, change direction, speed up, slow down, and maintain a constant speed; it can also cause an object to remain motionless. Do you agree or disagree with the following statement? Why or why not? Answer in your science notebooks. You may wish to project the statement on the board. The forces in the game of tug of war were balanced. Disagree. The forces were unbalanced because one team had more force and was able to win. If the forces were balanced, there would not have been a winner.

Forces & Motion

Motion A change in the position of an object A change in motion is caused by force

Force A push or pull on an object caused by the interaction of objects; either by contact or at a distance. Measured in units called newtons (N) Types of Force: Gravity Friction

Inertia An object at rest will remain at rest until acted upon by an unbalanced force. An object in motion will remain in motion until acted upon by an unbalanced force. When all forces acting on an object are equal (balanced).

Balanced Forces When all the forces acting on an object are equal. (Net force is zero.) Balanced forces do not cause a CHANGE in motion. In your notes, describe an example of a balanced force.

How Can Balanced Forces Affect Objects? Cause an object at rest to stay at rest or an object in motion to stay in motion (inertia) Cause an object moving at a constant speed to continue at a constant speed (inertia) In your notes, describe an example of a balanced force affecting an object.

Unbalanced Forces When all of the forces acting on an object are not equal. The forces can be in the same direction or in opposite directions. Unbalanced forces cause a change in motion. In your notes, describe an example of an unbalanced force.

How Can Unbalanced Forces Affect Objects? Acceleration is caused by unbalanced forces: Starting Stopping Speeding up Slowing down Changing direction In your notes, describe an example of an unbalanced force affecting an object.

Net Force The total of all forces acting on an object: Forces in the same direction are added. The object will move in the direction of the force. Forces in opposite directions are subtracted. An object will move in the direction of the greater force.

Calculating Net Force 30 N 10 N http://commons.wikimedia.org/wiki/File:Jack-in-the-box.jpg A child was playing with a jack in the box. The lid pushed down on the spring with 10 N of force, while the spring pushed up on the lid with 30 N of force. What is the net force applied by the spring? In your notebook, calculate the net force and show all of your work.

Check Your Answer 30 N 10 N http://commons.wikimedia.org/wiki/File:Jack-in-the-box.jpg A child was playing with a jack in the box. The lid pushed down on the spring with 10 N of force, while the spring pushed up on the lid with 30 N of force. What is the net force applied by the spring? 30 N up - 10 N down= 20 N up

Calculating Net Force Two competitors are playing tug of war. Tug of War Game 30 N 50 N Two competitors are playing tug of war. What is the net force? Which direction will the rope move? In your notebook, calculate the net force and show all of your work.

Check Your Answer Two competitors are playing tug of war. Tug of War Game 30 N 50 N Two competitors are playing tug of war. What is the net force? Which direction will the rope move? 50 N to the right – 30 N to the left = 20 N to the right

Force and Motion Task Cards Move around the room and answer the questions. This is an individual assignment and I expect you to THINK and calculate when needed. You will have the remainder of class to complete as much as you can. Record your answers on your answer sheet.

Learning Targets Tuesday, October 27, 2015 I can identify a force. I can demonstrate forces acting on an object. I can demonstrate how unbalanced forces change the direction of an object’s motion. I can calculate the net force. I can calculate force, mass, or acceleration by using the equation F = m X a

Mass and Gravity Mass is the amount of stuff (matter) in an object. Mass is measured in grams or kilograms. Gravity is a force that pulls objects toward the Earth. It can cause an unbalanced force to make objects start moving (ex. landslide, mudslide, avalanche)

Mass and Gravity Example: F=ma F= 25 kg x 9.8 m/s2 F = 245 N A person with a mass of 25 kg x 9.8 m/s2 gravitational acceleration is equal to 245 N of weight force. F= 25 kg x 9.8 m/s2 F = 245 N The person exerts 245 N of force on the ground. If the person went to the Moon, they would only weigh 1/6 of 245 N.

Force Force (N) = mass (kg) x acceleration (m/s2) F ÷ m x a F=ma

Force Acceleration (m/s2) = force (N) ÷ mass (kg) F ÷ m x a a=F/m

Force Mass (kg) = force (N) ÷ acceleration (m/s2) F ÷ m x a m=F/a

Practice Mass = Acceleration = The acceleration of a sprinter is 10 m/s2. The force exerted on the starting blocks is 650 N. What is the mass of the sprinter? Force = Mass = Acceleration =

Check Your Answer The acceleration of a sprinter is 10 m/s2. The force exerted on the starting blocks is 650 N. What is the mass of the sprinter? Force = 650 N Mass = 65 kg Acceleration = 10 m/s2 Mass = force (N) ÷ acceleration (m/s2) Mass = 650 (N) ÷ 10 (m/s2) Mass = 65 kg

Practice Mass = Acceleration = A 56 kg cart is accelerating at 15 m/s2. Calculate the force exerted on the cart? Force = Mass = Acceleration =

Check Your Answer A 56 kg cart is accelerating at 15 m/s2. Calculate the force exerted on the cart? Force = 840 N Mass = 56 kg Acceleration = 15 m/s2 Force (N) = mass (kg) x acceleration (m/s2) Force = 56 (kg) x 15 (m/s2)

Practice A boat is pulling a 54 kg wake boarder. The force the boat is exerting on her is 108 N. Calculate her acceleration. Force = Mass = Acceleration =

Check Your Answer A boat is pulling a 54 kg wake boarder. The force the boat is exerting on her is 108 N. Calculate her acceleration. Force = 108 N Mass = 54 kg Acceleration = 2 m/s2 Acceleration = force (N) ÷ mass (kg) Acceleration = 108 (N) ÷ 54 (kg) Acceleration = 2 m/s2

Force and Motion Task Cards Move around the room and answer the questions. This is an individual assignment and I expect you to THINK and calculate when needed. You will have the remainder of class to complete as much as you can. Record your answers on your answer sheet. Turn it in before you leave!

Learning Targets Thursday, October 29, 2015 I can identify a force. I can demonstrate forces acting on an object. I can demonstrate how unbalanced forces change the direction of an object’s motion. I can calculate the net force. I can calculate force, mass, or acceleration by using the equation F = m X a

Warm Up Thursday, October 29, 2015 Get out your white board and solve this equation: 365 X 2.5 = ?? Show your work!

1) John is driving East on I-30 at 75 mi/hr, he misses his exit so he turns around and starts driving West at 75 mi/hr. What happens to his speed and velocity? The velocity of the car changes, but the speed stays the same.

2) What is the average speed after 6 seconds? Is the object accelerating? 1 km/s No

3) What will be the result? 15 N 10 N The box will move to the right with a force of 5 N

4) Draw a distance/time graph that shows someone walking at a constant speed and then speeding up to a faster constant speed. D I S T A N C E TIME

5) List the formulas for calculating Speed, Distance, and Time 5) List the formulas for calculating Speed, Distance, and Time. 6) List the formulas for calculating Force, Mass, and Acceleration. S=d/t D=s x t T=d/s THINK!!

Review! https://www.youtube.com/watch?v=vl4g7T5gw1M This is an individual assignment. Use your notes and complete the review. This covers everything that will be on the test so make sure you KNOW it! We will go over it before class is over.

PRIDE - Cyberbullying https://goo.gl/aAVoa Take out a sheet of paper. Ball up the sheet of paper. Step on the paper ball. Try to straighten the paper as best as they can. “Look at the paper.” “No matter how hard you try to straighten the paper, it will not return to its original form.” “The wrinkles on your paper represent all of the hurtful words that are said to you and the words that you say to others that hurt them. It doesn’t matter if it is online or in person.” “These wrinkles are the scars that still remain on your life and the life of others.” “Even though you apologize, the scars are still there.” “Let’s have Integrity and Respect for others. Let’s stop bullying and take a stand against it!”

Friday, October 30, 2015 Unit 5 test! Use your test taking strategies!! Write on your test, show me what you are thinking as you work through problems. On the front of your test, write your speed triangle, force triangle, and 5 types of acceleration.