EQ What variables can you manipulate to affect

EQ: What variables can you manipulate to affect the movement of objects? Aim # 7: What is a vector quantity? Do Now: Use Guess to solve a person traveled 25 km in 30 minutes. How fast was the car driving?

Vector – Despicable Me �What the clip of Vector explaining how he commits crimes. �http: //www. youtube. com/watch? v=Kbr. EBp. Cw 3 Ag �Vectors can be represented with an arrow. � The length of the arrow is the magnitude. � The arrow points in the direction of the vector.

Mechanics Physical Quantities Variables Scalar Vector Quantity Variabl e Unit Quantity Time t (s) Acceleration a (m/s 2) Distance d (m) Speed v (m/s) Displaceme nt mass m (kg) Velocity v (m/s) Force F (N) (kgm/s 2) Variabl e Unit Energy E (J) Work W (J) (Nm) Momentum þ (rho) (kgm/s) Power P (J/s) (Nm/s) Impulse J (Ns)

What is displacement? How is it different from distance. �Distance is the amount of space you covered as you traveled. �Displacement is how far you traveled from start to finish. (Direction is a must). �You can show the displacement by drawing a vector arrow. �The length of the arrow is the magnitude. �The tail of the arrow starts where you started. �The head of the arrow points toward the direction you are traveling to. �The arrow ends where you stopped.

Distance vs. Displacement

Example �Max walked east �Given: d 1=26 m E, d 2=8 m W from school to his house 26 meters in 5 minutes. Then went to his friend’s house west 8 meters in 2 minutes. �What distance did Max’s cover? �What is his displacement from the school? t 1= 5 min , t 2 = 2 min �Unknown: distance =? ? ? m Displacement = ? ? m �Equation: distance = d 1+d 2 Displacement = d 1 -d 2 �Substitute: distance = 26 m+8 m �Solve: distance =34 m �Substitute: displacement =26 m-8 m �Solve: displacement = 18 m

What is velocity? And how do we measure it? �Average Velocity is the displacement divided by time. It is how far from the beginning you are, divided by the time, direction must be included. �Instantaneous velocity is a measure of how fast you are going at a certain point in time AND in what direction. �∆ Speed = (final distance – initial distance)/ time. �∆Velocity = displacement from origin/ time. Direction must be included.

Example � Max walked east from school to his house 26 meters in 5 minutes. Then went to his friend’s house west 8 meters in 2 minutes. � What was Max’s average speed? � What was max’s average velocity? � Given: t 1= 5 min, t 2 = 2 min Distance = 34 m, Displacement = 18 m east � Unknown: average speed =? ? ? m/s average velocity = ? ? m/s � Equation: v= d/t � Substitute: speed = 34 m/(5+2 min) � Solve: speed= (34 m/7 min)(1 min/60 sec) = 0. 08 m/s � Substitute: velocity =18 m/(5+2 min) � Solve: velocity= (18 m/7 min)(1 min/60 s) east

Talk Vector to me Game �Your objective it to get Ms. Adam 2. 0 from one side of the room to the other safely without hitting any objects in the way. Ms. Adam 2. 0 will only move if you give your instructions as a vector quantity. �Examples: �Walk left 3 steps. �Walk forward 1 meter.

Summary �How are vector quantities different from scalar quantities? �How do we represent vector quantities? �Try this problem: �Sam rode her bike east 20 meters in 2 mins, went up a hill east at a rate of 0. 8 m/s. Then she turned back going down the same hill west at a rate of 8 m/s. Did 15 meters in 30 s became tired and slowed down doing the last 5 meters in 120 s. What was Sam’s displacement, distance covered, average speed, and average velocity?