General Physics 1 - Lesson 3-1 PDF

GENERAL PHYSICS 1 SCALAR & VECTOR QUANTITIES Week 3 Session 1-4 Scalar Quantities Quantities that can be number with appropriate units. 1.Length / distance (d) 2. Speed (s) 3. Mass (m) 4. Time (t) 5. Temperature (t) 6. Energy (E) Length – The distance between any two points. Units: in...

GENERAL PHYSICS 1 SCALAR & VECTOR QUANTITIES Week 3 Session 1-4 Scalar Quantities Quantities that can be number with appropriate units. 1.Length / distance (d) 2. Speed (s) 3. Mass (m) 4. Time (t) 5. Temperature (t) 6. Energy (E) Length – The distance between any two points. Units: inches, feet/foot, miles, yard, light years SI unit: meter (m) Speed – distance traveled per unit of time. Units: Km/hr, mi/hr, cm/s SI unit: meters per seconds (m/s) Mass – amount of matter that a body contains. Units: tons, gram, pounds, slugs SI unit: kilogram (Kg) Time – interval separating two points of a continuum in which events occur irreversibly from the past through the present to the future. Unit: year, months, weeks, days, hour, minute SI unit: seconds (s) Temperature – The average kinetic energy of an object. Units: Fahrenheit, Celsius (centigrade), Rankine SI unit: Kelvin (K) Energy – is the capacity to do work. Units: kilowatt-hour, calorie SI unit: Joules (J) Vector Quantities Quantities which require magnitude and direction for their complete description. Denoted by an arrow. ( ) 1. Displacement ( d ) 2. Velocity ( v ) 3. Acceleration ( a ) 4. Force ( F )  Displacement – the straight line distance between starting and ending point. Units: inches, feet/foot, miles, yard SI unit: meter (m)  Velocity – the rate of change in displacement. Units: Km/hr, mi/hr, cm/s SI unit: m/s SPEED & VELOCITY FORMULA Where: d – distance (m) t – time (s) ∆x = displacement (m) Units: Km/hr, mi/hr, cm/s SI unit: m/s Acceleration – The rate of change in velocity. Acceleration formula: SI unit: meters/second squared Force – The product of mass and acceleration.  Force formula Unit: N or Kg. 𝒎/𝒔𝟐 Weight – Force of gravity. 𝐖 ≠ 𝒎 , W= 𝑭 Weight = 𝒎 𝒙 𝒈 Where: m = mass of the object g = acceleration due to gravity (9.8 m/𝑠 2 ) constant on Earth Think about this… If WORK is defined as a product of FORCE & DISPLACEMENT, is work a scalar quantity? Or a vector quantity? FORMULAS LEARNED F= 𝑚𝑎 𝑑 S= 𝑡 𝑑 V= 𝑡 𝑣𝑓𝑖𝑛𝑎𝑙 −𝑣𝑖𝑛𝑖𝑡𝑖𝑎𝑙 A= ∆𝑡  Problem Solving Identify the given Identify what is being asked Give the formula Derive if necessary Convert units if necessary Substitute the values Perform the calculations Box your final answer SAMPLE PROBLEMS  Jerry pushes a 3.2kg box with 1.5N of force. What is the resultant acceleration? Formula: Given: Derivation: Find: Mass = 3.2 Kg F = ma 𝐹 Force = 1.5 N Acceleration A= 𝑚 𝑣𝑓𝑖𝑛𝑎𝑙 −𝑣𝑖𝑛𝑖𝑡𝑖𝑎𝑙 A= ∆𝑡 Substitution: Final answer: 1.5 𝑁 𝑘𝑔.𝑚/𝑠 2 A= = 0.47 ( ) = 0.47 𝑚/𝑠 2 3.2 𝐾𝑔 𝐾𝑔 A car is moving at 80.0 mph. What acceleration would it have in 𝒎/𝒔𝟐 if it took 5.00 s to come to a complete stop? Conversion: 1 km = 0.621 miles Find: Formula: 1km = 1000m Given: 1 hr = 3,600 s acceleration 𝑣𝑓𝑖𝑛𝑎𝑙 −𝑣𝑖𝑛𝑖𝑡𝑖𝑎𝑙 𝑣𝑓 = 0 m/s A= 𝑚𝑖 1 𝑘𝑚 ∆𝑡 80.0 x = 128.8244767 km/hr 𝑣𝑖 = 80 mph 𝐻𝑟 0.621 𝑚𝑖 t = 5.0 s 𝑘𝑚 1𝑜𝑜𝑜 𝑚 𝑚 Substitution: 128.8244767 𝑥 = 128.8244767 ℎ𝑟 1 𝑘𝑚 ℎ𝑟 𝑚 𝑚 0 −35.8 A= 𝑠 𝑠 = -7.16 𝑚/𝑠 2 𝑚 1 ℎ𝑟 5.0 𝑠 −0 𝑠 128.8244767 x = 35.8 m/s ℎ𝑟 3,600 𝑠 Final answer: 𝒗𝒊𝒏𝒊𝒕𝒊𝒂𝒍 = 𝟑𝟓. 𝟖 𝒎/𝒔 = -7.16 𝑚/𝑠 2 a. Find the distance from A to C. b. Find the displacement from A to C. Solution A: Solution B: AB = 4m AB = 4m BC = 8m BC = 8m Distance AC = 4 m + 8 m Displacement 𝐴𝐶 2= 𝐴𝐵2 + 𝐵𝐶 2 AC = 12 m AC = 𝟒𝒎𝟐 + 𝟖𝒎𝟐 AC = 9 m Attendance code = the answer to this problem without the unit. (type the numbers only at 3 significant figures) Chief Flavio lives in Italy. He used 3.08 kilograms of pasta on Monday, then used 8.05 kilograms of pasta on Tuesday. What is the total weight of the pasta that chief Flavio used on Monday and Tuesday? END