force and motion fcat review
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- 1. E s s e n t i a l Q u e s t i o n s : Wh a ti sa When you jump up in c e ? f o r the air, what pulls you backdown W Earth? t to h ae f f e c t What pulls e magnet together oro r c it e d o a s a f pushes apart? The answer is. h a v e o na n o b j e c t ?
2. A FORCE is a push or pull that causes a change in motion. Nothing can change position, speed, or direction unless aforce acts on it. A book doesnt just fall off of a table by itself. A force has topush it! Forces can affect motion in several ways: They can make objects start moving They can make objects move faster They can make objects move slower They can make objects stop moving They can make objects change direction 3. Essential Questions: What happens when twounequal forces push an object in the same direction? What happens when two unequal forces push andobject in opposite directions? 4. E s s e n t i a l Q u e s t i o n s :Wh a ta r es o m eFriction- ise force that works against motion e st y p a s o ff o r c can makefthingsi slow down or o n or it (rc t i stop, , can keep things from moving at all greater between a v surfaces than betweeng r rough i t y ,msmooth one e t i ca g nf o r c e ) Ice skaters glide along? ice because there isthelittle friction between the blades and the ice. 5. E s s e n t i a l Q u e s t i o n s : Wh a t a r e s o m et y p e s o f f o r c e sGravity f r i c t ie o n , ( i st hu n i g r a v ia t y , v e r slm aa t g t n r e at c i t c i o f n o r c e )b e t w e e n? a n y t w oo b j e c t s w i t hm a s s . 6. E s s e n t i a lQ u e s t i o n s : Wh a t a r es o m e t y p e so ff o r c e s Magnetic ( f r i c that i o n iron isForce- anything t attracts , considered g r a Thats why y , clips are magnetic. v i t paper attracted to a magnet. Paper clips contain iron. Them a g called the magnetic force. force of a magnet is n e t i c A magnet is afpiece of metal that pulls? attractso r c e )or things which have iron or steel in them. The most common magnets are in the shape of a bar or horseshoe. The magnet is surrounded by a force field which attracts iron, especially at the poles. 7. M a g n e t s a r es u r r o u n d e d b y a f o r c e f i e l d w h i c ha t t r a c t si r o n ,e s p e c i a l l y a t t h e 8. Lets ReviewWhich of the following is an example of trying to increase the friction?A. Squirting oil in hingesB. Spreading grit on icy roadsC. Waxing the underneath of skis 9. Mr. Gates mops the gymnasium floor every day.When he finishes mopping, he puts up the signshown below. The effect of which force is weakenedwhen the floor is wet?A. frictionB. gravitationC. inertiaD. magnetism 10. Lets ReviewNS S N What is happening between these two magnets? A.) The magnets pull toward each other because like polesattract. B.) The magnets push away from each other because like polesattract. C.) The magnets pull toward each other because like polesrepel. D.) The magnets push away from each other because like polesrepel. 11. Lets ReviewOn which surface will a toy car travel the farthest?A. IceB. WoodC. Carpet 12. Lets ReviewWhich of the following is NOT a type of force?A. magneticB. frictionC. motionD. gravity 13. Characteristics of Motion The motion of an object can be described by its: Position Direction Speed Velocity Position, direction, speed, & velocity can be changed byforces that act on the object. 14. Position Position is the location of an object2 feet The dog is 2 feet away from the tree. This picture shows theposition of each object: the dog and the tree. 15. Direction Motion can also be described usingdirections such as north, south, east, &west. Direction of an object depends on thedirection of the force. It can be measuredwith a compass. The bird flew up, the car turned left, therabbit ran toward the gate, the dog ran awayfrom the house Objects can also move toward and away. 16. Speed Position and direction are helpful in describing motion.Yet motion also occurs over time. For example- You threw a football 20 meters. But did the football go 20 meters in 2 minutes? 2 seconds? Speed is the measurement of distance over time. You can use a stopwatch to measure speed 17. Velocity Velocity is the objects speed BUT includes direction Remember, DIRECTION includes north, south, east andwest- following the points of a compass. For example- the football that was thrown 20 meters in 2 seconds is traveling 10 meters per second (20/2 = 10). You MUST include direction for velocity. So your answer might really be 10 meters per second west! States the direction the ball traveled 18. Measuring Motion Scientists use many tools to measuremotion: Commonly used to measure direction isthe compass. A meterstick is commonly used tomeasure distance between one positionand another. A stopwatch is used to measure time 19. Lets Review Which of the following is the BESTdescription of the position of theeraser? A.) The eraser is near the pencil B.) The eraser is to the left ofthe pencil 4 cm C.) The eraser is 4 cm awayfrom the pencil D.) The eraser is 4 cm to theleft of the pencil 20. Lets Review What is the speed of a hockey puck thatmoves 45 meters in 5 seconds? A.) 45 meters per second B.) 17 meters per second C.) 9 meters per second D.) 5 meters per second 21. Lets Review What is velocity? A.) speed and position B.) speed and direction C.) position and direction D.) direction and time 22. Newtons First Law of MotionAn object at rest tends to stay at rest and an object inmotion tends to stay in motion unless acted upon by an unbalanced force. 23. Newtons First Law of Motion With no net force acting upon it, an object at rest tends to stay at rest, an object in motion tends to stay in motion. Both objects will continue with the same inertia keeping the same velocity. A soccer ball doesnt just rollacross the field on its own. It takes a force (such as a kick) to move the ball. Once the ball moves, it doesnt just move forever. Eventually it will stop. Earths gravity and friction stop moving objects. 24. Newtons Second Law ofMotionThe acceleration of an object depends on themass of the object and the size of the forceacting on it.Acceleration: a measurement of how quickly an object is changing speed. 25. NEWTONS SECONDLAWThe more mass an object has, the harder it is to accelerate.The less mass an object has, the easier it is to accelerate. 26. Newtons Third Law of MotionFor every action there is an equal and opposite reaction. 27. Forces occur in pairs- for every action there is an = and opposite reaction.As the runners footpushes on thestarting block(action force), thestarting block isexerting a force onthe runners foot(reaction force). 28. Lets ReviewA(n) __________ is a push or a pull.B) motionD) velocityF) AccelerationD) force 29. Lets Review Which of the following is not an acceleration? A) stopping your bike at an intersection B) slowing your bike ride so you can make it up a hill C) riding your bike faster when you head down a hill D) riding your bike straight down the street at a constantspeed 30. Lets ReviewForces that cancel each other are called __________ forces. A) neutral B) balanced C) inactivated D) null 31. Lets Review Whenever one object exerts a force on anotherobject, the second object ALWAYS exerts anequal force back on the first object. A.) True B.) False 32. Lets Review Forces always occur in ______________. A.) Triplets B.) Pairs C.) by themselves D.) either singly or in pairs 33. Lets Review Newtons first law of motion states that __________. A) an object will remain at rest or keep moving with aconstant velocity unless a force acts on it B) acceleration is calculated by dividing the force exerted onan object by the mass of the object C) when a force acts on an object, its acceleration is in thesame direction as the force D) when a force is applied on an object, there is an equalforce applied by the object in the opposite direction 34. Lets Review__________ is a force that resists motion between twosurfaces. A) Resistance B) Inertia C) Friction D) Acceleration 35. Essential Question: Why do we need simple machines? What are the 6simple machines?Work means that we are exerting force and moving something.The 6 simple machines make our work easier. We wont have touse as much force with our simple machines. 36. The Wheel and Axle Two or more wheels areconnected by an axle The wheel turns with oraround the axle 37. Pulley A pulley is a wheel with a rope running overit. The wheel has a groove, called a sheave,and it keeps the rope from slipping off thewheel. Remember, since there is a wheel in apulley there also has to be an axle! 38. Lever There are two parts to a lever: The Lever Arm: the arm that moves Fulcrum: the support or balancethat does NOT move 39. The Wedge A wedge is a special kind of inclined plane made of two slopes, back to back. Wedges can be used to move things apart. Wedges can change the direction of the applied force. A wedge is used to split, tighten, or secure a hold. A wedge is usually a triangle shape with a sharp point. If you apply force at one end, the wedge will go between something, in this case an ax splits a piece of wood. 40. The Inclined Plane The inclined plane is a planesurface set at an angle, otherthan a right angle, against ahorizontal surface. The inclinedplane permits one to overcome alarge resistance by applying arelatively small force through alonger distance than the load isto be raised. A screw is a rod with an inclined plane wrapped around it. The spiraling inclined plane forms ridges which are called threads. 41. Lets ReviewWhich of the following is NOT a simple machine?A.) inclined planeB.) wedgeC.) elevatorD.) screw 42. Lets ReviewA fork is an example of a:A.) pulleyB.) wedgeC.) wheel and axleD.) lever 43. Lets ReviewA saw, a knife, and a doorstop are all examples of what type of simple machine?A.) inclined