360 likes | 498 Views
PHSC 001 PREPARTORY PHYSICAL SCIENCE. Welcome! Academic Year 2013/2014 Semester 1. COURSE DESCRIPTION
E N D
PHSC 001PREPARTORY PHYSICAL SCIENCE Welcome! Academic Year 2013/2014Semester 1 Ms. Eman Alqurashi
COURSE DESCRIPTION This course offers an overview of the physics, chemistry, earth sciences and astronomy. All topics will be treated with the minimum need for mathematics; essentially it is a non calculus based course. It covers the fundamental concepts of mechanics, electricity and magnetism, periodic table, atomic models, and introductory concepts relating to earth science and astronomy. TEXT BOOKs Chapters handouts will be uploaded on E-learning. Ms. Eman Alqurashi
Examinations & grades: Assignment 0% Quizzes 10 % Laboratory assignment 10 % Major 1 20 % Major 2 20 % Laboratory Exam/Project 10 % Final Exam 30 % Lecture notes and problems are available on E-learning Ms. Eman Alqurashi
Office Number: A0-090 Eman.Alqurashi@yuc.edu.sa Ms. Eman Alqurashi
Chapter-1 Motion Ms. Eman Alqurashi
Lecture Outlines At the End of this Lecture you will be able to • Objective 1:Explain the properties of motion • Position. • speed . • Velocity. • Acceleration. • Objective 2:Usethe metric and SI system of measurement. • Objective 3:Differentiate between speed and velocity. • Objective 4:Differentiate between velocity and acceleration. • Objective 5:Analyzeproblem statements and translate the information into a formula. Ms. Eman Alqurashi
1.1 Motion What is motion? Motion is a change in the object’s position with respect to time. Describe the motion of the car? • Motion is relativeto something not moving(tree for example). • Distance “d” is changing with respect to time “t”. • Motion can be along straight line or curve. Credit: Physics forscientists and engineers, a strategic approach” by Randall D. Knight Pearson-Addison Wesley 2004. Ms. Eman Alqurashi
Straight line motion Curve motion Vertical Horizontal Credit: Physics forscientists and engineers, a strategic approach” by Randall D. Knight Pearson-Addison Wesley 2004. Ms. Eman Alqurashi
Types of motion Ms. Eman Alqurashi
Credit: Physics for scientists and engineers strategic approach” by Randall D. Knight, Pearson-Addison Wesley 2004. Ms. Eman Alqurashi
Quantities Temperature , mass Speed , volume Time , distance. Force , weight velocity ,acceleration displacement. Ms. Eman Alqurashi
1.3.1 Measurement Systems Top three English system (foot, slug, and second) system. “cgs” System (centimeter, gram, second). Metric or it’s SI system “mks” (meter, kilogram, and second). The most common used Ms. Eman Alqurashi
Measurements in Metric and SI Systems Ms. Eman Alqurashi
In this course we will use the metric system. This system employs prefixes or powers of 10 to describe large or small quantities. • Common Prefixes Examples Pg.7-Ch1 Credit: “Integrated science”, 3rd Ed. By Tirllery, Enger, and Ross, McGraw Hill 2007. Ms. Eman Alqurashi
1.3.2 Scientific Notation In science, scientists use scientific notation to write very large or very small numbers e.g. the scientific notation for a large number such as 56 000, 000 is 5.6 × 107 ,and for a small number such as 0.000 00056 is 5.6 ×10-7. A. If the number is greater than 1 Move the decimal point to the left after the first digit to give a number between 1 and 9. The spaces moved are shown as a power of ten. The power is positive. Example: 34 0000 = 3.4 × 105 (5 spaces moved to the left). B. IfThe number is less than 1 Move the decimal point to the right after the first digital point to give a number between 1 and 9. The spaces moved are shown as a power of ten. The power is negative. Example: 0.00378 = 3.78 × 10-3 (3 spaces moved to the right). Ms. Eman Alqurashi
Example 1.3 Pg. 8 • Write the following numbers in scientific notation • (1) Diameter of earth is 12 800 000 m = _______________ m • (2) Mass of a human is 78 kg = _______________ kg • (3) Length of a virus is 0.000 03 cm = _______________ cm Ms. Eman Alqurashi
Units Conversion • How to convert units? • You will need; • conversion factor and conversion ratio • 1 m=100 cm is a conversion factor • 1m/100cm=1 is a conversion ratio • The steps to convert the units as follow: • 1. Write down the given number with its unwanted unit. • 2. Multiply this by a ratio of 1. • The ratio is written from a given conversion factor and it consists of two units, the unwanted unit and the wanted unit. Ms. Eman Alqurashi
some useful conversion factors Ms. Eman Alqurashi
Examples: 1. Convert 54 m to km given that 1km=1000m 1km/1000m=1, and 1000m/1km=1. Which ratio you use? 2. Convert your age 20y into days. 3. Convert 60 pm to m Step1: 54 m Step2: (54 m)(1km/1000m)= 54/1000 km= 0.054 =5.4 x10-2 km Step1: 20y Step2: (20y)(365days/1y)= 7300 days Ms. Eman Alqurashi
is a vector quantity represents the distance between the initial point and final point of an object. is a scalar quantity represents the interval between two points. B B A A The length of the curved line. The length and direction of the straight line. Ms. Eman Alqurashi
1.4 Motion properties: Speed , Velocity and Acceleration 1.4.1 Speed Speed“ν”is a measure of how fast or how slowly an object moves. speed = distance covered travel time • It is defined as the distance traveled per unit of time. ν= d t Mathematically we can write: where ν is the speed dis the distance t is the travel time The SI unit of speed is (m ∕ s) . Ms. Eman Alqurashi
The speed is not constant an average speed is used, represented by a dash over the letter v. ν = d t For Instance, if you drive 300 km distance from Yanbu to Jeddah in 3 hr, then your average speed is = 300 = 10 km/h 3 ν • The speed is at particular instant an Instantaneous speed is measured, Ms. Eman Alqurashi
A speedometer shows a car’s instantaneous speed. • The instantaneous speed is the actual speed an object has at any moment. Ms. Eman Alqurashi
Example: • Which of the following could be a speed measurement? • 2.5 meters • 2.5 seconds/meter • 2.5 meters/second • 2.5 meters/second/second Ms. Eman Alqurashi
1.4.2 Velocity Velocity ““is a measure of the speed and it’s direction. • It is defined as the displacement traveled per unit of time. speed = displacement travel time D t Mathematically we can write: ν= Credit: “Integrated science”, 3rd Ed. By Tirllery, Enger, and Ross, McGraw Hill 2007 Ms. Eman Alqurashi
Speedis the Rate of Distance 0 10 10 ft. Seconds Position A Position B Ms. Eman Alqurashi
Velocityis the Rate of Distance in a Specified Direction 0 10 10 ft. Seconds Position A Position B North West East South Ms. Eman Alqurashi
Velocity of an object tells us both magnitude and direction vector quantity • Speedof an object tells us the magnitude only scalar quantity Speed = magnitude of the velocity • Constant Speed: means steady speed( no changing with time). • Constant velocity: means both speed and direction are constant ( no changing with time and in straight line). Ms. Eman Alqurashi
Constant velocity Variable velocity Ms. Eman Alqurashi
1.4.3 Acceleration Acceleration a “ “ is a measure of how fast or how slowly is the change in velocity. • It is defined as the change in velocity over time. Acceleration= change in velocity time interval • Mathematically we can write: where a is the a cceleration The SI unit of acceleration is ( m ∕ s²) . ∆v is the change in velocity ( vfinal − vinitial ) ∆t is the time interval. Ms. Eman Alqurashi
Is It Vector or Scalar? Ms. Eman Alqurashi
The acceleration is not constant an average acceleration is used, represented by a dash over the letter a. Example: A car accelerate in a straight line from 50 km/hour to 70km/hour in 5 sec .What is its acceleration ? vinitial= 50 km/hour = 50 × 1000 = 13.89 m/s 3600 vfinal = 70km/hour = 70 × 1000 = 19.44 m/s 3600 time = 5 sec Acceleration = change in velocity = vfinal − vinitial time interval time interval = 19.44 − 13.89 = 1.11 m/s² 5 Ms. Eman Alqurashi
Examples A car moving east starts from rest to 20m/sec. The change occurs in 5 seconds. Finds its average acceleration. The driver of a car steps on the brakes, and the velocity drops from 20 m/sec east to 10 m/sec east in a time of 2 seconds. What is the acceleration? Ms. Eman Alqurashi
1.5 Problem Solving Method Steps to solve the problems: 1. Read the problem carefully. Read it at least twice, slowly and completely from the beginning to the end. 2. Make a sketch of the problem if it is necessary. You can substitute or represent any object by a dot or a box. 3. Write down all given information (data) with units. Look at some terms that carry some information. For example, motion from rest means initial velocity equals zero. Also, the term „smooth surface‟ indicates no friction . 4. Write down the unknown quantity or quantities the question asked for. 5. Write down the basic equation or formula that relates all the known and the unknown quantities . 6. Find the working equation or formula for the unknown quantity 7. Substitute the data in the working equation, including the units. Verify your work Ms. Eman Alqurashi
Worksheet Page (16-20) Ms. Eman Alqurashi