A Car Accelerating at a Green Light Balanced or Unbalanced

Answer Key th 7 Accelerated Science 1st Semester Study Guide Scientific Processes Be able to explain and identify from a given science experiment scenario the following: Independent, dependent, and control variables, control group, hypothesis, problem, data, analysis, and conclusion. Al wonders if adding salt to water will affect how long it takes the water to freeze. Al thinks that saltwater will freeze more quickly than fresh water. He decides to check his hypothesis by conducting an experiment. Al takes two ice trays and fills one with distilled water and the other with distilled water that has two tablespoons of salt added. He makes sure he puts exactly the same amount of water in each ice tray. Al takes the trays and puts them side by side in the freezer. Al checks the ice trays every 10 minutes to see if the water in each tray has begun to freeze. Al finds that after 20 minutes the water in the ice tray without the salt has started to form ice, while the ice tray with the saltwater is still completely liquid. After reading the scenario identify the following: a) Problem: Does adding salt to water affect its freezing time? b) Hypothesis: If more salt is added to water, then it will freeze faster because it lowers the freezing point of water. c) Independent variable: Amount of salt d) Dependent variable: Time it takes to freeze water. e) Control variables: Amount of water, same freezer, type of water, type of salt f) Control Group: Water with no salt. g) Experimental Group: water with salt Know the difference between observation & inference 1. What is the difference between an observation and an inference? An observation is the data measured, collected, perceived or noticed, especially during an experiment. An inference is drawing a conclusion based on data and observation 2. A time machine has been invented that travels into the past and takes pictures, sending them to the present. You are asked to look at one of the pictures and interpret what you see. Put an “O” before the statements that are observations and an “I” before the statements that are inferences. a) O - The volcano is erupting. b) I - The camptosaurus is going to eat the stegosaurus. c) I - The stegosaurus will run into the water to escape. d) O - The camptosaurus is leaving tracks in the ground. e) O - The ground where the camptosaurus is walking is wet. f) O - There are plants growing in the water. g) I - The camptosaurus is going into the water to eat the plants. h) O - There is a tree growing next to the river. i) O - The tree looks like a palm tree. j) I - The climate is warm. k) O - The stegosaurus is eating the plant. Know the difference between qualitative & quantitative observations. 3. Determine which of the following statements are quantitative and which are qualitative. a) quantitative Thor is 6ft 5in tall. b) qualitative Superman is taller than Thor. c) qualitative Batman’s cowl is black. d) quantitative The Batmobile has four tires. e) quantitative Ironman’s suit is made from 1,234,567 pieces. Be able to interpret graphs for variables, relationships, and trends. 4. Use the graph to the right to answer the following questions: a.) What is the independent variable? Year b.) What is the dependent variable? Value in $ c.) What type of relationship is present? (Positive, negative, null) Negative d.) What story does the graph tell you? Cars lose value over time. Safety/ Equipment Know basic safety rules. Be able to accurately read a TBB, a thermometer, a metric ruler and a graduated cylinder. 5. Answer the following science measurement problems: a.) Read the following triple beam scale and determine the mass. Triple Beam Balances measure in grams. 538.9g b.) Read the following graduated cylinder and determine the volume in mL c.) What is the curve at the top of the liquid called? meniscus d.) What is the temperature in Celsius? 44°C Metrics: Know the names of the metric measurements. 30ml 45ml 86ml Be able to convert between different metric prefixes. 6. What are the base metric (SI) units for the following? a.) Distance: meter (m) b.) Mass : Gram (g) c.) Volume: Liter (L) d.) Temperature: Celsius (C) e.) Force: Newton (N) f.) Frequency: Hertz (Hz) 7. What scientist is responsible for the metric system? LaVosier 8. What scientist is responsible for creating the metric temperature scale? Anders Celsius 9. What scientist is responsible for the modern theory of light? Sir Isaac Newton 10. 1234 kg = 1.234 g 729 cm = 7.29m Density: Understand Density and its formula. a.) What is the formula used to calculate density? D = m/v 1201 mL = .1201L 53ml b.) What is the density of a piece of wood that has a mass of 25.0 grams and a volume of 29.4 cm3? D = m/v D = 25/29.4 D = .85g/cm3 c.) Based on the chart below, circle the substances that would sink in water and put a square around those that would float. Substance Gasoline Ice Magnesium Iron Oak Milk Density 0.70 g/cm3 0.93 g/cm3 1.7 g/cm3 7.8 g/cm3 0.6 – 0.9 g/cm3 1.03 g/cm3 Speed & Motion - Be able to calculate for speed, distance, or time. 11. Draw the speed, distance, time triangle of awesome. 12. What is the difference between speed & velocity? Velocity includes direction 13. Calculate the following: a) The distance between Heysham and the Isle of Man is 80 km. A hovercraft travels at 50 km per hour. How long does the journey take? T = d/s T = 80/50 T = 1.6 hours b) A girl ran 105 meters in 15 seconds. What was her speed? S = d/t S = 105/15 S=7 m/s c) What distance would a car travel after 4 hours travelling at 60mph? D = ts D = 4 • 60 D = 240 miles d) A horse travels at 12 km/hour. How long will it take to travel 18km? T = d/s T = 18/12 T = 1.5 hours Acceleration: Be able to calculate for acceleration. 14. What is the formula for acceleration if your knowns change in velocity and time? 15. List the three ways that an object can accelerate – speed up, slow down, change direction. 16. Calculate the following: a.) Calculate the acceleration of a car that goes from 100 m/sec to a speed of 65 m/sec in 5 seconds. 𝐴= 65−100 5 𝐴= −35 5 𝐴 = −7𝑚/𝑠 2 b.) Toni is riding her bike across a parking lot. She is heading east at 100 meters per second. Ten seconds later, Toni is heading east at 15 meters per second. What was Toni’s acceleration? 𝐴= 65−100 5 𝐴= −35 5 𝐴 = −7𝑚/𝑠 2 Be able to interpret a Position (Distance)/Time graph. 17. The distance, by boat, from Poole Quay to Wareham is 12 miles. The diagram shows the distancetime graph of a boat trip from Poole Quay to Wareham and back. 12 10 Distance 8 from Poole Quay (miles) 6 4 2 0 1100 1200 1300 Time 1400 1500 a.) Describe what happened to the speed of the boat at 1200 hours. Slows down. b.) How long did the boat stay in Wareham? 70 minutes c.) What was the average speed of the boat on the return journey from Wareham to Poole Quay? Time = 90min or 1.5 hr, Distance = 12 miles S = d/t S = 12/1.5 S = 8 mph Be able to draw & interpret Speed-time graphs Time (hours) Above is a velocity-time graph of a moving car. Answer the following questions using the graph. a.) At what time was the car stopped? Between .7 & .8 b.) At what time did the car have the greatest velocity? Between .2 & .4 c.) What was the greatest velocity? 60 km/h d.) At what time(s) was the car accelerating? (Accelerating = speed up or slow down) Between 0-.2, .4-.7, .8-1.0 e.) How fast was the car going at 1.0h? 40 km/h f.) What is the acceleration at 0.9 hr? 10km/s Force & Friction Be able to calculate net force & interpret force diagrams. 18. What is force? Force is a push or a pull 5N 25 N 19. Calculate the net force of the following a.) Is this force balanced or unbalanced? (Why?) Unbalanced – they are not equal. b.) What is the net force? 25-5 = 10N 20. Define and list the four types of friction. Give an example of each. Sliding, Rolling, Fluid, Static 21. What two things can affect the amount of friction that is present on an object? Type of Surface & How hard the objects are pushing together 22. What two things affect gravity? Mass & Distance 23. How fast is acceleration if the only thing acting on it is gravity? 9.8 m/s2 Newton’s Laws of Motion 24. What is the vocabulary word associate with the tendency of an object to resist change? Inertia 25. What is the difference between mass and weight? Mass is that amount of matter is an object, is constant & not dependent of location. Weight is the measure of the pull of gravity on an object & changes with location. 26. Explain why you would weigh less on the moon than on Earth? Moon has less gravity, so the weight is less but mass remains the same. 27. State Newton’s First Law of Motion. a) Explain the motions of a hockey puck during a hockey game in terms of Newton's first law. The hockey puck will continue to move on the ice due to inertia until something like a hockey stick stops it. b) Bob and Larry were in a car going to the football game. Suddenly, the car crashes into a pole. (No one is injured.) Bob had his seatbelt on, but Larry had forgot to put his seatbelt on. Describe or draw what happened to the guys according to Newton’s 1st law. 28. What does a Newton measure? What units is it measured in? Force, Newtons. 29. Newton’s Second Law of Motion. a) What equation is associated with Newton’s Second Law of Motion? F = ma b) Calculate the force on an object that has a mass of 12 kg and an acceleration of 4 m/s2. F = ma F = 12 • 4 F = 48 N c) Bugs Bunny sits on the ground. He is being pulled along the ground by Elmer Fudd with 16N of force at a rate of 2 m/s2 What is Bugs Bunny’s mass? M = f/a M= 16/2 M=8kg d) A net force of 10 Newtons acts on a box which has a mass of 2 kg. What will be the acceleration of the box? A= f/m A=10/2 A=5m/s/s 30. Explain Newton’s Third Law of Motion. For every action there is an equal & opposite reaction 31. For each of the following interactions, identify action and reaction forces (action-reaction pairs): a) A hammer hits a nail - Action Nail pushes back on hammer - Rxn b) Earth’s gravity pulls down on you – Action You pull back on the Earth - Rxn c) A helicopter blade pushes air downward - Action Air pushes the helicopter blade up. - Rxn d) You step off a curb – Action Curb pushes you forward - Rxn e) You pat your friend on the back - Action Your friend’s back pushed back on your hand - Rxn f) A wave hits a rocky shore – Action Shore pushes the wave back - Rxn 32. Solve for the unknown: Mason is on a train that is at rest. It suddenly speeds up to 500km/hr. He travels for two hours. The train is traveling north. What is his acceleration? What is his velocity? 𝐴= 𝑉𝑓 − 𝑉𝐼 𝑇 𝐴= 500− 0 2 𝐴= 500 2 A = 250 km/h/s V = 250km/h/s North 33. Solve for the unknown: Sean has decided to go bungee jumping. If he has a mass of 70km and he accelerates towards Earth at a rate of 9.8m/s² due to gravity, what is the force on Sean? (Don’t’ forget to show your work and label your answer!) F=ma F= 70 • 9.8 F=686N Electromagnetic Spectrum, Light, and Waves: 34. Waves transfer energy not matter. 35. What is the difference between mechanical & electromagnetic waves? Mechanical waves need a medium; em waves do not. 36. Define & draw concave and convex. 37. Draw a convex mirror and show how the light will reflect. 38. Draw a convex lens and show what will happen when light passes through. 39. Define frequency and hertz. Frequency I show many waves per second. Hertz is the unit of frequency. 40. List the EMS in order form slowest wave to fastest wave. Which one has the most energy? The least energy? Radio, Microwave, Infrared, Visible Light, Ultraviolet, X-Ray, Gamma Rays Gamma Rays have the most energy & Radio Waves the least. 41. List the colors of light from smallest wave to largest wave. Which colors are faster than green? Violet, Indigo, Blue, Green, Yellow, Orange, Red Blue, Indigo, Violet are faster than green. 42. Define & illustrate refraction, reflection, and diffraction. Refraction: Light is bent as it goes THROUGH a different material Reflected: Light bounces off the object Diffracted: Light is bent AROUND the object. 43. When all colors reflect off a surface what color do the produce? White Light 44. When all colors are absorbed what color do they produce? Black 45. A blue shirt is reflecting what colors? Blue 46. Define transparent, translucent, and opaque. Provide examples 47. Draw and Label a longitudinal wave: compressions, rarefactions, direction of wave, amplitude 48. Draw a transverse wave and label the crest, trough, wave length, amplitude, the direction of the wave. 49. Draw and label 6 Hz. 50. Compare & contrast AM & FM Radio waves. AM Waves change amplitude, FM changes Frequency 51. Our modern understanding of light and color begins with the scientist, Sir Isaac Newton and a series of experiments that he publishes in 1672. He is the first to understand the rainbow — he refracts white light with a prism, resolving it into its component colors: red, orange, yellow, green, blue and violet. SOUND: 52. What is the hearing range for a normal adult? 20 – 20,000Hz 53. Define sound. A type of longitudinal wave that originates as the vibration of a medium (such as a person's vocal cords or a guitar string) and travels through gases, liquids, and elastic solids as variations of pressure and density. 54. What 2 things are necessary to produce sound? Vibrations and matter 55. Draw and label a sound wave. 56. What medium does sound travel fastest through – air, water, solids? Why? Travels fastest through solids because the molecules are closest together 57. Loudness is measured in what units? Decibels 58. Frequency is measured in what units? Hertz 59. Why can’t Noise Induced Hearing Loss be repaired? The hair cells in the cochlea are destroyed and can be replaced or repaired.