Presentation on theme: "GPS SP1. Students will analyze the relationships between force, mass, gravity, and the motion of objects. –b. Compare and contrast scalar and vector quantities."— Presentation transcript:
GPS SP1. Students will analyze the relationships between force, mass, gravity, and the motion of objects. –b. Compare and contrast scalar and vector quantities.
SCALARS AND VECTORS Scalars only have magnitude (ex. 50 m) Vectors have magnitude and direction (ex. 50 m, North) When you combine two or more vectors the sum is called the resultant. For example in 1-D: 50 m North and 30 m South; the resultant is 20 m North (+50 m + (-30 m))
VECTOR BASICS Images: tors/u3l1a.cfm
THE RESULTANT IN ONE DIMENSION
DIRECTION Images: 3l1a.cfm
THE RESULTANT IN TWO DIMENSIONS (X AND Y) ors/U3l1b.cfm
PROPERTIES OF VECTORS Vectors can be moved parallel to themselves in a diagram. Vectors can be added in any order. For example, A + B is the same as B + A To subtract a vector, add its opposite. SIGNS (DIRECTION) ARE VERY IMPORTANT!!! Multiplying or dividing vectors by scalars results in vectors. For example: When you divide displacement ( x or y) by time (s) the result is velocity (v).
RESULTANTS CAN BE DETERMINE GRAPHICALLY OR ALGEBRACIALLY When determining the resultant graphically you must be careful of several factors. Your scale must be determined and measured accurately with a ruler. Your angles (directions) must be done with a protractor. ALWAYS DRAW YOUR VECTORS FROM HEAD TO TAIL!!!!! The resultant is always from the head of your last vector to the tail of your first vector. HEAD TAIL
GRAPHICALLY DETERMINING A RESULTANT
DETERMINING RESULTANTS BY ALGEBRA AND TRIGONOMETRY You must use the Pythagorean theorem and trigonometry to determine a resultant. WE ONLY USE DEGREES IN THIS CLASS!! NO RADIANS!!!! You must know SOHCAHTOA!! You must be able to use your calculator correctly! The resultant is always from the head of your last vector to the tail of your first vector. Direction is always from the tail of the first vector.
REAL LIFE VECTORS
ANSWERS TO PRACTICE PRACTICE A: km at º W of N OR km at 63.44º N of W PRACTICE B: 50 km at 53.13º S of WOR 50 km at 36.87º W of S
PROBLEMS 1 and 2 Which of the following quantities are scalars, and which are vectors? (A) the acceleration of a plane as it takes off (B) the number of passengers on the plane (C) the duration of the flight (D) the displacement of the flight (E) the amount of fuel required for the flight? A roller coaster moves 85 m horizontally, then travels 45 m at an angle of 30° above the horizontal. What is its displacement from its starting point?(graphical techniques)
ANSWERS 30° RESULTANT 126 m at 10° above the horizontal (A) vector (B) scalar (C) scalar (D) vector (E) scalar
PROBLEMS 3 and 4 A novice pilot sets a planes controls, thinking the plane will fly at 250 km/hr to the north. If the wind blows at 75 km/hr toward the southeast, what is the planes resultant velocity? Use graphical techniques. While flying over the Grand Canyon, the pilot slows the planes engines down to one-half the velocity of the last problem. If the winds velocity is still 75 km/h toward the southeast, what will the planes new resultant velocity be?
ANSWERS 204 km/h at 75° north of east 89 km/h at 54° north of east
PROBLEM The water used in many fountains is recycled. For instance, a single water particle in a fountain travels through an 85 m system and then returns to the same point. What is the displacement of a water particle during one cycle?