2 Lesson 3.01 What is Force? Key Points: -In science, a Force is anything that can cause an object with mass to move.-Mass is the amount of matter or stuff in an object. Don't confuse mass with weight. They are related, but they are not the same. Weight is how hard gravity pulls on an object, where mass is the amount of matter in an object. In the United States, we measure weight in pounds. Mass is measured in kilograms.-Contact Forces are applied when two or more objects physically touch.-Distance Forces are applied when two or more objects do not touch.Questions: Which example below displays a Contact Force andwhich displays a Distance Force?Grabbing a metal toy out of the toilet with your hand.Grabbing a metal toy out of the toilet with a magnet.
3 Lesson 3.02 Contact Forces Key Points: -There are three types of contact forces that we are going to go over:*Applied Force (An applied force is any force that is directly applied to an object by a person or other object. For example, pushing, throwing, pulling, or hitting an object).*Friction (Friction is a force that is exerted by a surface on an object that is sliding across it. Friction will cause an object to slow down or make it hard to get the object to move).*Normal Force (The normal force is a force that is released by non moving objects. This is a support force).Questions: What type of force is displayed in the examples below:-A wall supports you if you lean on it.-Throwing a baseball.-A sled slows down on a rocky hill path.
4 Lesson 3.03 Distance Forces: Gravity Key Points:-Distance Forces cause objects that have mass to move without physical touch. Skydiving is a great example of our first distance force…Gravity.-Gravity is an attractive force.*We know that we don’t fly out into space because of gravity.*We know that if you trip and fall it’s because of gravity.*We know that “what goes up must come down” because of gravity.The first thing that affects Gravity is Mass.The more Mass an object has the more Gravity it has.The second thing that affects Gravity is Distance.The Closer you are to an object the Stronger the pull of Gravity.3. When there is no Air Resistance (no air), objects will be affected the sameby Gravity. Just think of Air Resistance as a type of Friction between the airand a moving object.Questions: Which falls faster when dropped on Earth, a Hammer or a Feather?Which falls faster when dropped on the Moon, a Hammer or a Feather?
5 Lesson 3.04 Distance Forces: Magnetism Lab Key Points:A Magnet is an object that can produce a Magnetic Force.1. All Magnets have a north pole (N) and a south pole (S). You can see these represented by the letters N and S on the ends of a magnet.2. The Magnetic Force in a Magnet will attract objects that are made of metal, and it will have no effect on objects not made of metal. This means the Magnetic Force only works on objects made of metal.3. Two Magnets will Attract each other if the Opposite Poles are put toward each other.4. Two Magnets will Repel each other is the Same Poles are put toward each other.Questions: Do the Magnetic Poles below Attract or Repel?N NS SN SS N
6 Lesson 3.05 Distance Forces: Electrical Lab Key Points:-An Electrical Force is a force that is created between objects that have a Charge.-Particles and Objects can have one of 3 different Charges.These Charges are the driving forces behind the Electrical Force.*Some particles are Negatively charged.*Some particles are Positively charged.*Some particles do not have a charge (Neutral).-When Same Charges are near each other, they will Repel.-When Opposite Charges are near each other, they will Attract.-When a Neutral and a Charged object are near each other, they Attract.-When 2 Neutral Objects are near each other, Nothing happens.Questions: Do the following combinations Attract or Repel or Do Nothing?- and Neutral and –+ and and Neutral- and Neutral and Neutral+ and -
7 Lesson 3.06 Balanced and Unbalanced Forces Key Points:-When Forces act on an object and do not change the speed of the object, this is called a Balanced Force.-When Forces act on an object that causes the speed or the direction of the object to change, this is called an Unbalanced Force.Questions: Are the following examples displaying a Balanced or an Unbalanced Force?A car sitting in the driveway.A car being towed.A car moving.
8 Lesson 3.07 Graphing Constant Speed Key Points:-When Graphing the Speed of an object or of 2 racing objects, make sure that your Line Graph includes an X-axis that is Horizontal and a Y-axis that is Vertical.-The X-axis will display the Time.-The Y-axis will display the Distance.Speed = Distance / TimeSpeed is usually measured in Miles per Hour (mph) orKilometers per Hour (kmph)Your Graph will be able to show you which object went the farthest!Question: If 2 cars are racing, is the Force acting upon themBalanced or Unbalanced?