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Geometry Vectors CONFIDENTIAL
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Warm up Find each measure. Round lengths to the nearest tenth and angle measures to the nearest degree. 1) BC ) m/B ) m/C CONFIDENTIAL
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Vectors You can think of a vector as a directed line
segment. The vector below line segment. The vector below may be named AB or v CONFIDENTIAL
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A vector can also be named using component from. The
3 C 2 A vector can also be named using component from. The Component from 4 {x, y} of a vector lists the horizontal and vertical change from the initial point to the terminal point. The Component from of CD is {2,3}. CONFIDENTIAL
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Writing Vectors in Component From
Subtract the coordinates of the initial point from the coordinates of the terminal point. Substitute the coordinate of the given points simplify. CONFIDENTIAL
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Now you try! 1) Write each vector in component from. a)
b) The vector with initial point L(-1,1) and terminal point M(6,2) CONFIDENTIAL
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The magnitude of a vector is its length. The magnitude
is written |AB| or | v |. When a vector is used to represent speed in a given direction, the magnitude of the vector equals the speed. For example, if a vector represents the course a kayaker paddles, the magnitude of the vector is the kayaker’s speed. CONFIDENTIAL
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Finding the magnitude of a Vector
Step 1 Draw the vector on a coordinate plane. Use the origin as the initial point. Then (4,-2) is the terminal point. Step 2 Find the magnitude. Use the Distance Formula. CONFIDENTIAL
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Now you try! 2)Draw the vector (-3,1) on a coordinate plane. Fine its
magnitude to the nearest tenth. CONFIDENTIAL
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The direction of a vector is the angle that it
makes with a horizontal line. This angle is measured counterclockwise from the positive x -axis. The direction of AB is 60˚. CONFIDENTIAL
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The direction of a vector can also be given as a bearing
relative to the compass directions north, south, east, and west . AB has a bearing of N 30˚ E. N B 30˚ W E A S CONFIDENTIAL
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Finding the Direction of a vector
A wind velocity is given by the vector (2,5). Draw the vector on a coordinate plane. Find the direction of the vector to the nearest degree. Step 1 Draw the vector on a coordinate plane. Use the origin as the initial point. Next Page -> CONFIDENTIAL
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Step 2 Find the direction.
Draw right triangle ABC as shown. /A is the angle formed by the vector and the x –axis, and CONFIDENTIAL
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Now you try! 3) The force exerted by a tugboat is given by the
vector (7,3). Draw the vector on a coordinate plane. Find the direction of the vector to the nearest degree. CONFIDENTIAL
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Two vectors are equal vector if they have the same
magnitude and the same direction For example, u = v. Equal vector do not have to have the same initial point and terminal point. | u | = | v | = 2√5 v Next Page -> CONFIDENTIAL
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Two vectors are parallel vectors if they have the same
direction or if they have opposite directions. They may have different magnitudes. For example, w || x . equal vectors are always parallel vectors. |w| = 2√5 |x| =√5 x w CONFIDENTIAL
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Identifying Equal and Parallel Vectors
Identify each of the following. A) AB = GH Identify vectors with the same magnitude and direction. B) Parallel vectors AB || GH and CD || EF Identify vectors with the same or opposite directions. CONFIDENTIAL
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Now you try! 4) Identify each of the following. Equal vectors
Parallel vectors M R P N Y S X Q CONFIDENTIAL
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The resultant vector is the vector that represents the
sum of two given vectors. To add two vectors geometrically, you can use the head-to-tail method or the parallelogram method. CONFIDENTIAL
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Vector Addition METHOD EXAMPLE Head-to-tail method
Place the initial point (tail) of the second vector. On the terminal point (head) of the first vector. The resultant is the vector that joins the initial point of the first vector to the terminal point of the second vector. u = v v u Next Page -> CONFIDENTIAL
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Vector Addition METHOD EXAMPLE Parallelogram Method
Use the same initial point for both of the given vectors. Create a parallelogram by adding a copy of each vector at the terminal point (head) of the other vector. The resultant vector is a diagonal of the parallelogram formed. u = v v u CONFIDENTIAL
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To add vectors numerically, and their components.
If u = (x ,y ) and v = (x ,y ), then u + v =(x +x , y +y ). 1 1 2 2 1 2 1 2 CONFIDENTIAL
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Step 1 Sketch vectors for the kayaker and the current.
Sports Application A kayaker leaves shore at a bearing of N 55˚ E and paddles at a constant speed of 3 mi/h. There is 1 mi/h current moving due east. What are the kayak’s actual speed and direction? Round the speed to the nearest tenth and the direction to the nearest degree. Step 1 Sketch vectors for the kayaker and the current. N N kayaker Current 3 y 55˚ 35˚ W E W E 1 X S S CONFIDENTIAL Next Page ->
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Step 2 Write the vector for the kayaker in component from
Step 2 Write the vector for the kayaker in component from. The kayaker’s vector has a magnitude of 3 mi/h and makes an angle of 35˚ with the x –axis. N N kayaker Current 3 y 55˚ 35˚ W E W E 1 X S S CONFIDENTIAL Next Page ->
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Step 3 Write the vector for the current in component from.
Since the current moves 1 mi/h in the direction of the x –axis, it has a horizontal component of 1 and vertical component of 0. So its vector is (1,0). N N Current kayaker 3 y 55˚ 35˚ W E E W 1 X S S Next Page -> CONFIDENTIAL
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Step 4 Find and sketch the resultant vector AB.
Add the components of the kayaker’s vector and the current’s vector. (2.5, 1.7) + (1,0) = (3.5, 1.7) The resultant vector in the component from is (3.5, 1.7). N resultant B (3.5, 1.7) 1.7 A W E C 3.5 S Next Page -> CONFIDENTIAL
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Step 5 Find the magnitude and direction of the resultant vector.
The magnitude of the resultant vector is the kayak’s actual speed. The angle measure formed by the resultant vector gives the kayak’s actual direction. N resultant B (3.5, 1.7) 1.7 A W E C 3.5 S CONFIDENTIAL
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5) What if….? Suppose the kayaker in Example 5 instead
Now you try! 5) What if….? Suppose the kayaker in Example 5 instead Paddles at 4 mi/h at a bearing of N 20˚ E. What are the kayak’s actual speed and direction? Round the speed to the nearest tenth and the direction to the nearest degree. CONFIDENTIAL
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Now some practice problems for you!
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Assessment Write each vector in component from. 1) PQ
2) AC with A(1,2) and C(6,5) Q P CONFIDENTIAL
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Draw each vector on a coordinate plane
Draw each vector on a coordinate plane. Find its magnitude to the nearest tenth. 3) (1,4) ) (-3,-2) ) (5, -3) CONFIDENTIAL
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6) A river’s current is the given by the vector (4,6).
Draw each vector on a coordinate plane. Find the direction of the vector to the nearest degree. 6) A river’s current is the given by the vector (4,6). 7) The path of a hiker is given by the vector(6,3). CONFIDENTIAL
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Identify each of the following.
8) Equal vectors in diagram 1 9) Parallel vectors in diagram 2 Diagram 1 Diagram 2 Q G X B N D R H F C A M Y E P S CONFIDENTIAL
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10) To reach a campsite, a hiker first walks for 2 mi at a bearing of N 40˚ E. Then he walks 3 mi due east. What are the magnitude and direction of his hike from his starting point to the campsite? Round the distance to the nearest tenth of a mile and the direction to the nearest degree. N 3 mi campsite 2 mi 40˚ W E S CONFIDENTIAL
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Vectors Let’s review You can think of a vector as a directed line
segment. The vector below line segment. The vector below may be named AB or v CONFIDENTIAL
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A vector can also be named using component from. The
3 C 2 A vector can also be named using component from. The Component from 36 {x, y} of a vector lists the horizontal and vertical change from the initial point to the terminal point. The Component from of CD is {2,3}. CONFIDENTIAL
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Writing Vectors in Component From
Subtract the coordinates of the initial point from the coordinates of the terminal point. Substitute the coordinate of the given points simplify. CONFIDENTIAL
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The magnitude of a vector is its length. The magnitude
is written |AB| or | v |. When a vector is used to represent speed in a given direction, the magnitude of the vector equals the speed. For example, if a vector represents the course a kayaker paddles, the magnitude of the vector is the kayaker’s speed. CONFIDENTIAL
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Finding the magnitude of a Vector
Step 1 Draw the vector on a coordinate plane. Use the origin as the initial point. Then (4,-2) is the terminal point. Step 2 Find the magnitude. Use the Distance Formula. CONFIDENTIAL
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The direction of a vector is the angle that it
makes with a horizontal line. This angle is measured counterclockwise from the positive x -axis. The direction of AB is 60˚. CONFIDENTIAL
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The direction of a vector can also be given as a bearing
relative to the compass directions north, south, east, and west . AB has a bearing of N 30˚ E. N B 30˚ W E A S CONFIDENTIAL
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Finding the Direction of a vector
A wind velocity is given by the vector (2,5). Draw the vector on a coordinate plane. Find the direction of the vector to the nearest degree. Step 1 Draw the vector on a coordinate plane. Use the origin as the initial point. Next Page -> CONFIDENTIAL
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Step 2 Find the direction.
Draw right triangle ABC as shown. /A is the angle formed by the vector and the x –axis, and CONFIDENTIAL
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Two vectors are equal vector if they have the same
magnitude and the same direction For example, u = v. Equal vector do not have to have the same initial point and terminal point. | u | = | v | = 2√5 v Next Page -> CONFIDENTIAL
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Two vectors are parallel vectors if they have the same
direction or if they have opposite directions. They may have different magnitudes. For example, w || x . equal vectors are always parallel vectors. |w| = 2√5 |x| =√5 x w CONFIDENTIAL
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Identifying Equal and Parallel Vectors Identify each of the following.
A) AB = GH Identify vectors with the same magnitude and direction. B) Parallel vectors AB || GH and CD || EF Identify vectors with the same or opposite directions. CONFIDENTIAL
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The resultant vector is the vector that represents the
sum of two given vectors. To add two vectors geometrically, you can use the head-to-tail method or the parallelogram method. CONFIDENTIAL
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Vector Addition METHOD EXAMPLE Head-to-tail method
Place the initial point (tail) of the second vector. On the terminal point (head) of the first vector. The resultant is the vector that joins the initial point of the first vector to the terminal point of the second vector. u = v v u Next Page -> CONFIDENTIAL
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Vector Addition METHOD EXAMPLE Parallelogram Method
Use the same initial point for both of the given vectors. Create a parallelogram by adding a copy of each vector at the terminal point (head) of the other vector. The resultant vector is a diagonal of the parallelogram formed. u = v v u CONFIDENTIAL
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To add vectors numerically, and their components.
If u = (x ,y ) and v = (x ,y ), then u + v =(x +x , y +y ). 1 1 2 2 1 2 1 2 CONFIDENTIAL
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Step 1 Sketch vectors for the kayaker and the current.
Sports Application A kayaker leaves shore at a bearing of N 55˚ E and paddles at a constant speed of 3 mi/h. There is 1 mi/h current moving due east. What are the kayak’s actual speed and direction? Round the speed to the nearest tenth and the direction to the nearest degree. Step 1 Sketch vectors for the kayaker and the current. N N kayaker Current 3 y 55˚ 35˚ W E W E 1 X S S CONFIDENTIAL Next Page ->
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Step 2 Write the vector for the kayaker in component from
Step 2 Write the vector for the kayaker in component from. The kayaker’s vector has a magnitude of 3 mi/h and makes an angle of 35˚ with the x –axis. N N kayaker Current 3 y 55˚ 35˚ W E W E 1 X S S CONFIDENTIAL Next Page ->
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Step 3 Write the vector for the current in component from.
Since the current moves 1 mi/h in the direction of the x –axis, it has a horizontal component of 1 and vertical component of 0. So its vector is (1,0). N N Current kayaker 3 y 55˚ 35˚ W E E W 1 X S S Next Page -> CONFIDENTIAL
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Step 4 Find and sketch the resultant vector AB.
Add the components of the kayaker’s vector and the current’s vector. (2.5, 1.7) + (1,0) = (3.5, 1.7) The resultant vector in the component from is (3.5, 1.7). N resultant B (3.5, 1.7) 1.7 A W E C 3.5 S Next Page -> CONFIDENTIAL
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Step 5 Find the magnitude and direction of the resultant vector.
The magnitude of the resultant vector is the kayak’s actual speed. The angle measure formed by the resultant vector gives the kayak’s actual direction. N resultant B (3.5, 1.7) 1.7 A W E C 3.5 S CONFIDENTIAL
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You did a great job today!
CONFIDENTIAL
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