PHYSICS REVIEWER PDF

Measurement - It is the process of comparing a specific quantity of matter with an agreed standard. Why do we measure? - It helps us to know more about the things around us - We measure when we buy goods in the market - We measure the temperature of a place to wear appropriate clothes - I...

Measurement - It is the process of comparing a specific quantity of matter with an agreed standard. Why do we measure? - It helps us to know more about the things around us - We measure when we buy goods in the market - We measure the temperature of a place to wear appropriate clothes - It is important to our health because we need to measure the dosage of the medicine we take whenever we are sick. - We need to measure the ingredients when cooking to come up with a healthy delicious food Metric and English Conversions Quantity Metric English Conversion Mass g, kg lb, oz 1 lb = 454 g 1 kg = 2.2 lb 1 oz = 28. 35 g Length cm, m, km in, ft, mi 1 in = 2.54 cm 1 m = 39.37 in 1 ft = 12 in 1 mi = 1.609 km 1km = 0.62137 mi Volume mL, L qt, pints, cups, tsp, 1 qt = 946 mL tbsp, fl, oz, gal 1 L = 1.057 qt 1 L = 2.12 pints 1 L = 4.23 cups 1 tsp = 4.93 mL 1 tbsp = 14.79 mL 1 fl oz = 29.6 mL 1 gal = 3.79 L Two kinds of quantities of Measurements - Fundamental quantities of measurement - Derived quantities of measurement International System of Units (SI UNITS) - Evolved from the metric system - Provides additional and more accurate units of measurement Accuracy - Indicates how close a measurement is to the true or accepted value Precision - Refers to the closeness of measurements within a set of data Sources of errors in Measurement Random error - results from unpredictable or inevitable changes during data measurement. Systematic errors - comes from the measuring instrument in the design of the experiment. Why are physical measurements never exact? - Human and mechanical factors contribute to the results of measurement. Error - is the deviation of a measured value from the expected or true value Uncertainty - is a way or expressing this error Scientific Notation - Is the system of expressing products with a number between 1 and multiplied by an appropriate power of 10. Examples: 1000 = 1 x 103 0.00001 = 1 x 10−5 Kinematic Quantities MECHANICS - the study of motion two general parts: 1. Kinematics - mathematical description of motion Eg.: position, speed, acceleration 2. Dynamics - study of the causes of motion Eg.: when an object falls, you can say that gravity is the cause of its falling motion Position - fundamental concept of describing motion Distance - the length of the total path the object has move - Scalar quantity, SI unit-meter Displacement - The shortest length the initial position and the position of the object - Vector quantity, SI unit- meter Speed - It is the measure of how fast or slow a body moves. = v = speed d = distance t = time Velocity - It is a quantity that contains both the speed and direction of motion. = v = velocity d = displacement t = time Common Violations - Overtaking - Loading in unloading zone or in prohibited area - Jaywalking - Beating the red light - Speeding - Tailgating - Illegal lane change - Reckless driving - Ignoring railroad signs - Not yielding at pedestrian crossings - Violating the don't walk signal Acceleration - It is the measure of how fast or slow velocity changes = a = acceleration v = velocity t = time SI UNIT - m/ 2 Mass - Amount of matter in an object Weight - Pull of gravity on an object’s location Volume - Amount of space occupied by an object - For a regularly shaped solid such as cube, the volume is obtained by multiplying the solid’s length (l), width (w), and height (h). - v=lxwxh Density - Mass per unit of volume it occupies = p = (rho) density ( 3 ) m = mass (kg) v = volume