MRS. KALSCHEUR S PHYSICS MID-TERM REVIEW

Transcription

1 MRS. KALSCHEUR S PHYSICS MID-TERM REVIEW FORMULAS Acceleration = (Final Velocity - Initial Velocity)/Time [(Vf - Vi)/t] Average Speed = Total Distance Traveled/Total Time it took Force = Mass x Acceleration (F = ma) [Net Force] Acceleration = Force/Mass (a = F/m) [Net Force] Mass = Force/Acceleration (M = F/a) Momentum = Mass x Velocity Speed = Distance/Time (s = d/t) Distance = Speed x Time (d = s x t) [Net Force] [*per scenario] Time = Distance/Speed (t = d/s) Velocity= Distance/Time with a given direction (V = d/t with a given direction) Distance = Velocity x Time with a given direction (d = V x t with a given direction) Time = Distance/Velocity with a given direction (t = d/v with a given direction) SI UNITS Acceleration m/s 2 km/hr 2 Distance m km Force N (Newtons) [1 N = 1 kg x m/s 2 ] Mass g kg Momentum kg x m/s Speed m/s km/hr Time s hr min Velocity m/s with a direction km/hr with a direction 1 of 6

2 CONVERSIONS 1 Hour = 60 Minutes 1 Minute = 60 Seconds 1 Kilometer = 1,000 meters CLASS ITEMS TO REVIEW Calculating Speed Worksheet Distance, Time, Speed Practice Problems Worksheet Formula Challenge Worksheet Graphing Speed Worksheet Motion Graphs Packet Motion Practice Problems Worksheet Multiple Representations of Motion Packet (*Motion Map Packet under classwork on web page) Which Law? Worksheet August 3-4, 2016 PowerPoint Presentation August 15, 2016 PowerPoint Presentation Week of August 29, 2016 PowerPoint Presentations VOCABULARY Acceleration: the rate at which velocity changes; increasing or decreasing speed and changing direction Balanced Forces: all forces acting on an object are equal; there is NO MOTION Distance-Time Graph: A distance-time graph tells us how far an object has moved with time. The steeper the graph, the faster the motion. A horizontal line means the object is not changing its 2 of 6

3 position - it is not moving, it is at rest. A downward sloping line means the object is returning to the start. Fluid Friction: a solid object moves through a fluid (doesn t have to be a liquid think AIR RESISTANCE) Free Fall: when the only force acting on a falling object is gravity Inertia: the tendency of an object to resist a change in its motion Mass: the amount of matter in an object Newton s Law of Conservation of Momentum: states that, in the absence of outside forces, the total momentum of objects that interact does not change; the amount of momentum is the same before and after they interact Newton s Law of Universal Gravitation: states that the force of gravity acts between all objects in the universe; any two objects in the universe, without exception, attract each other Reference Point: a place or object used for comparisons to determine if something is in motion Rolling Friction: object rolls across a surface Sliding Friction: occurs when two solid surfaces slide over each other Slope: equals rise over run (rise/run) Speed: the distance the object travels per unit of time Speed-Time Graph (*also called Velocity-Time Graph): A speed-time graph shows us how the speed of a moving object changes with time. The steeper the graph, the greater the acceleration. A horizontal line means the object is moving at a constant speed. A downward sloping line means the object is slowing down. Static Friction: the friction that acts on objects that are not moving Unbalanced Forces: one or more forces acting on an object are stronger than others; there is MOTION; A NET FORCE Velocity: is speed with a given direction (*make sure you understand this is with direction) Weight: the force of gravity on a person or object on the surface of a planet SIR ISAAC NEWTON S LAWS KEYWORDS: The First Law: Force and Inertia The Second Law: Force, Mass and Acceleration The Third Law: Action and Reaction 3 of 6

4 NEWTON S 2ND LAW OF MOTION You push an object, and it accelerates. You push harder on the same object, and it accelerates more quickly. Yet, when you push just as hard on a heavier object, it accelerates much more slowly. Why? It turns out that force, mass, and acceleration are related. The relationship is stated by Newton's second law of motion, Force=Mass x Acceleration -or- F=ma where F is the force, m is the mass, and a is the acceleration. The units are Newtons (N) for force, kilograms (kg) for mass, and meters per second squared (m/s 2 ) for acceleration. The other forms of the equation can be used to solve for mass or acceleration. m=f/a and a=f/m Example: Engineers at the Johnson Space Center must determine the net force needed for a rocket to achieve an acceleration of 70 m/s 2. If the mass of the rocket is 45,000 kg, how much net force must the rocket develop? Answer: Using Newton s 2nd Law of Motion formula F=ma. F= (45,000 kg)(70 m/s 2 ) = 3,150,000 kg m/s 2. F = 3,150,000 N. (Note that the units kg m/s 2 and newtons are equivalent; that is, 1 kg m/s 2.) CALCULATING NET FORCE slideplayer.com 4 of 6

5 Top Ten Test-Taking Tips for Students Here are the top ten tips to success! 1. Have a Positive Attitude Approach the big test as you'd approach a giant jigsaw puzzle. It might be tough, but you can do it! A positive attitude goes a long way toward success. 2. Make a Plan The week before the test, ask your teacher what the test is going to cover. Is it from the textbook only? Class notes? Can you use your calculator? If you've been absent, talk to friends about material you may have missed. Make a list of the most important topics to be covered and use that as a guide when you study. Circle items that you know will require extra time. Be sure to plan extra time to study the most challenging topics. (Use the study guides provided) 3. The Night Before Cramming doesn't work. If you've followed a study plan, the night before the test you should do a quick review and get to bed early. Remember, your brain and body need sleep to function well, so don't stay up late! 4. The Morning of the Test Did you know that you think better when you have a full stomach? So don't skip breakfast the morning of the test. Get to school early and do a ten-minute power study right before the test, so your brain is turned on and tuned up. 5. Test Time Before the test begins, make sure you have everything you'll need - scratch paper, extra pencils, your calculator (if you're allowed to use it). Understand how the test is scored: Do you lose points for incorrect answers? Or is it better to make guesses when you're not sure of the answer? Read the instructions! You want to make sure you are marking answers correctly. 5 of 6

6 6. Manage Your Time Scan through the test quickly before starting. Answering the easy questions first can be a time saver and a confidence builder. Plus, it saves more time in the end for you to focus on the hard stuff. 7. I'm Stuck! Those tricky problems can knock you off balance. Don't get worried or frustrated. Reread the question to make sure you understand it, and then try to solve it the best way you know how. If you're still stuck, circle it and move on. You can come back to it later. What if you have no idea about the answer? Review your options and make the best guess you can, but only if you don't lose points for wrong answers. 8. Multiple-Choice Questions The process of elimination can help you choose the correct answer in a multiple-choice question. Start by crossing off the answers that couldn't be right. Then spend your time focusing on the possible correct choices before selecting your answer. 9. Neatness Counts If your 4s look like 9s, it could be a problem. Be sure that your writing is legible and that you erase your mistakes. For machine-scored tests, fill in the spaces carefully. 10. I'm Done! Not so fast - when you complete the last item on the test, remember that you're not done yet. First, check the clock and go back to review your answers, making sure that you didn't make any careless mistakes (such as putting the right answer in the wrong place or skipping a question). Spend the last remaining minutes going over the hardest problems before you turn in your test. Follow these test tips, and you'll know you did your best - congratulations! 6 of 6