2Warm-up What two factors effect the force of gravity? How do balanced and unbalanced forces effect motion?
3Forces (pages 21-28) Essential Questions Finish from other day if you need to. What is a force?What is an example of a contact and a noncontact force?What two factors determine the force of gravity?How does friction effect motion?How do balanced and unbalanced forces effect motion?
4Forces (pages 21-28) Essential Questions 1. What is a force? push or a pull 2. What is an example of a contact and a noncontact force? contact – friction noncontact - gravity 3. What two factors determine the force of gravity? mass and distance 4. How does friction effect motion? works in the opposite direction of motion 5. How do balanced and unbalanced forces effect motion? balanced – stationary or constant speed and direction unbalanced - acceleration
5Check for Understanding Describe how forces apply to the people in these videos.Jeb CorlissKen BlockTravis PastranaRemote KontrolDanny MacAskillUse four vocabulary terms in your descriptionForceNoncontactContactGravityFrictionBalancedUnbalanced
6DOL A car is traveling at a constant speed and direction. What is a contact force acting on the car?What is a noncontact force acting on the car?How does friction effect the car?Are the forces balanced or unbalanced? Explain.
8FrictionDescribe 3 areas or instances where having more friction on a bicycle is a “good thing”.Describe 3 areas or instances where having more friction on a bicycle is a “not-so-good thing”?
9Other forces Magnetic Aerodynamic drag (fluid friction) Thrust Lift Buoyant
10Balanced and unbalanced forces NotesSim QuestionsBalanced forcesNo motionConstant speed in same directionUnbalanced forcesMotionChanging speed or directionWhat if gravity and buoyancy are unbalanced?What if gravity and buoyancy are balanced?Why does weight change in water but not mass?
11Force diagram vocabulary Gravity – always straight downNormal – opposes gravity, when object is resting on a solid surfaceBuoyant – opposes gravity when object is suspended in a fluid (liquid or gas)Applied – “push or pull”Friction – opposes applied force
12Warm-up - Copy Force diagrams Gravity – straight downNormal – opposes gravity when object is resting on a solid surfaceApplied – push or pullFriction – opposes applied force and motion
13Aerodynamics of flight What are the four forces impacting flight?How is lift generated?What is the relationship between weight and lift?What is the relationship between thrust and drag?
18-List 5 ways the bike reduces aerodynamic drag -List 5 ways the bike reduces aerodynamic drag. -List 5 ways the rider reduces aerodynamic drag.
19Force diagram problems A 1000 N couch is being pushed with 450 N of force to right. The friction is 500 N.Are the forces balanced or unbalanced?Will the couch move?Normal1000NFriction500NApplied450 NGravity1000N
20Warm-upIf an object is being pushed with 200 N of force and has 250 N of static friction, will it move? Explain.
21Force diagram practice A 20,000 N (down) plane has 10,000 N of drag (back) and 50,000 N of thrust (forward) and is able to generate 30,000 N of lift (up). Sketch a force diagram, identify the forces as balanced or unbalanced, and decide if the object is moving.A piece of wood weighing 100 N in placed in a tub of water. The buoyant force on the wood is equal to 100 N. Sketch a force diagram, identify the forces as balanced or unbalanced, and decide if the object is moving.How could one team beat another team in tug-of-war if both teams have the same overall weight and both teams are pulling with the same force? Sketch a force diagram to help explain your answer.
22DOLWhy must engineers consider forces when designing different modes of transportation? Give specific examples.Force diagramsSketch a force diagram showing an 800 N football player pushing a 500 N tackling dummy with 1000 N of force. The friction is 250 N.Are the forces balanced or unbalanced?Is the tackling dummy moving?