Review for FinalVocabulary…..• Gene transfer – moving of a gene from one organism to another• Transgenic animal – animal that has had foreign DNA put into its cells• Cerebrum – part of the brain where thinking takes place• Biotechnology – technology used in agriculture, food science, and medicine• Impulses – a message carried by a neuron• Neurons – the basic functioning units of the nervous system• Cloning – copying a plant or animal• Microinjection – injecting DNA into a cell using a small needle and microscope• Carcinogens – promote the growth of cancer cells• Synapse – the space between neurons• Depressant – drug that slows down the processes of the nervous system• Stimulant – drug that speeds up the activities of the nervous system
More Vocabulary….The central nervous system is made up of the brain and spinal cordArtificial insemination is when a male’s sperm (semen) is inserted into a femaleA force is a push or pull with direction
Displacement vs Distance Distance – how far something moved (meters) Displacement – how far, AND what direction something moved (meters to the NW) Is the red or yellow line distance? DISTANCE Red is distance = how far moved Finish Yellow is displacement = how far and what direction DISPLACEMENT Displacement is always a straight line, and will always be shorter than distanceStart
What is a Force?A force is a push or pull on an object with directionA force has a size AND a directionIs a force a scalar or vector quantity?Examples of forces:-Pushing your book across a table-Pushing a boxA force must have adirection, so it is a vector quantity
The Units of ForceForce is measured in NewtonsNewton is abbreviated “N”Newton (N) = kg x m/s2m/s2 is accelerationSo, one Newton is the amount of force that will accelerate a 1 kgobject at 1m/s2 Force is mass x acceleration f ma
Forces are shown as arrows, or vectorsThe longer the arrow (vector), the greater the forceThe direction of the arrow shows you the direction of the force 10 N east N 5 N east Vectors
Adding ForcesMore than one force on an object will be added.So, if two people are pushing something east, one pushing with5N, the other with 10N, what will be the net force on the box? 10 N east + 5 N east 15 N east = net force
Balanced and Unbalances ForcesBalanced forces: when 2 forces cancel each other (no movement) 10 N force east 10 N force west f 10 N 10 N 0NThere is no movement in balanced forcesExample of a balanced force??
Balanced and Unbalances ForcesUnbalanced forces: forces that do not cancel (create movement) 10 N force east 15 N force west 5 N west f 15 N 10 N 5 NwestUnbalanced forces always create movementExample of an unbalanced force??
Draw a Balanced and Unbalanced force in Your NotebooksUnbalanced forces (create movement) 10 N force east 15 N force west 5 N west Movement to the west Balanced forces (do NOT create movement)
Newton’s First Law (law of inertia) What is Newton’s 1st law?? • Objects in motion stay in motion unless a force is applied to them • Objects at rest stay at rest unless a force is applied to them What is inertia?? • Tendency of an object to resist change in its state of motionExamples of inertia:-A person flies forward when a car stops-A person flying over bike handlebars
Newton’s Second LawForce is equal to an object’s mass times its acceleration f ma N = kg x m/s2 N/kg = m/s2 m/s2 = acceleration
Newton’s Third LawAll forces exist in pairsFor every action, there is an equal and opposite reactionTHERE CANNOT BE ONE FORCE
Complete Questions in Notebook1. Using the equation to the right, what will be more difficult to accelerate, an object with a f ma large or a small mass?2. Explain Newton’s first, second and third laws and draw a picture to help explain each law.
ANSWERS1. Using the equation to the right, what will be more difficult to accelerate, an object with a large or a small mass? f maa = f/m so it will be easy to accelerate (move) objects with smallmass, and hard to accelerate objects with a large mass.1. Explain Newton’s first, second and third laws and draw a picture to help explain each law.Newton’s first law says that moving objects will keep moving, andthat stationary (=not moving) objects will not move. It issometimes called the law of inertia. Inertia is the tendency ofobjects to maintain their current state of motion. A man notwearing a seatbelt and flying out of a car is an example of inertia.Newton’s second law states that the force on an object is equal toits mass times its acceleration (f=ma). Newton’s third law saysthat for every action, there is an equal and opposite reaction.From this, we can deduce that forces must exist in pairs, and thatthere can never be a single force.
Review for Final1. The displacement of a man walking on a curved road is (greater than, less thanor equal to) his distance traveled? Less than2. When you walk across the room the force on your feet is (greater than, less thanor equal to) the force on the floor? Equal to
Mass vs WeightMass is NOT the same as weight!!Mass – measure of how much matter an object containsWeight – an object’s mass (Kg) times its acceleration (m/s2)Mass does not change with locationWeight does change with locationWeight is a force and it is a vector quantityMass is a scalar quantity with no directionWeight is measured in NewtonsMass is measured in Kg
This online weightcalculator toldme how much I weigh on different planets
Does Bart Weigh More on Earth or Jupiter?Bart weighs more on Jupiterbecause it’s a larger planetand has a strongergravitational pull
Is Bart’s Mass Greater on Earth or Jupiter? 50 Kg 50 Kg Bart’s mass is the same everywhere in the universe. Mass never changes.
What is the difference between mass and weight?Write answer in your notebooks…Weight is measured in Newtons and is the product of mass times acceleration.Mass is how much matter an object contains and is measured in kg. The mass ofan object will be the same anywhere in the universe, while the weight of anobject will change depending on its location. Mass is a scalar quantity, whileweight is a vector quantity which means it has direction.
How to calculate acceleration…A dog speeds up from 0 m/s to 21 m/s in 3 seconds.Calculate the dog’s acceleration in your notebooks21 m/s – 0 m/s = 21 m/s per 3 seconds21 m/s/3s = 7 m/s/s or 7 m/s2Is acceleration a vector or scalar quantity?VECTOR!!Why is it m/s2 and not m/s/s? They are the same thing…m/s/s = m/s * 1/s = m/s2m/s/s = m/s2