Vectors and Scalars Distance and Displacement Physics is

Vectors and Scalars Distance and Displacement

� Physics is a math based science studying motion and the forces that cause it. There are two types of measurements we use in Physics. � Vectors � Scalars

Scalars � Scalars are units of measurement with only magnitude. � Magnitude is a fancy word for “any value and unit of measurement. ” � Examples of Scalar values: 5 meters. 25º C. � Example units: Physical properties (volume, mass, color), temperature, distance, speed.

Vectors � Vectors are magnitudes with direction. � Vectors are always in straight lines. � Examples: 10 meters East. 5 m/h North. � Example Units: Forces and work, electrical current, magnetic and electric fields, displacement, velocity, and acceleration.

� We draw vectors with arrows. 50 km East 10 km West 5 km North The Arrows have to be drawn in proportion to one another, so bigger values get bigger arrows, and vice versa.

Distance � Distance is how far you go. � Distance is a scalar value.

Displacement � Displacement is how far between two points (A and B) along the path traveled. ◦ In other words: This can be the distance between your starting point and your ending point. Billy Ended Here. Billy Started Here

� When calculating distance, ADD all the values. It’s how far you traveled. � When calculating Displacement, we find the amount of space between our first point (starting point) and our second point (ending point). Or the difference between points A and B.

Calculating Distance � If I walk 5 m East and then 3 m East again, what’s my total distance? � 5 m 3 m � 5 m+3 m=8 m. Our total distance is 8 m.

� If Atlanta Braves player Justin Upton hits yet another homerun, what is the distance he’s traveled around the bases? � 27 m 27 m (answer on next slide)

� Because the bases are 27 m apart on a baseball field, Justin Upton ran 27 m from home to first, 27 m from first to second, 27 m from second to third, and 27 m from third back to home plate. � So that’s 27 m+27 m+27 m = 108 m is his total distance.

Calculating Displacement � The batteries in the remote died, you have to turn on the TV by hand. You walk 7 m across the room, turn on the TV, then walk 5 m back to crash on the comfy chair. What is your displacement? � 7 m � 5 m � We walked 7 m one way, then backtracked 5 m. So we subtract. 7 m-5 m=2 m displacement.

� If Atlanta Braves player Justin Upton hits yet another homerun, what is his displacement around the field? � 27 m 27 m (answer on next slide)

� So Justin Upton hit the homerun and he ran around all the bases, but he hit the ball from home plate and ended back up at home plate from his homerun. He ended up right where he started. � So while his distance traveled was 108 m (we figured that out 3 slides back), his displacement is 0 because the two points were the same (he both started and ended at home plate).

� When calculating displacement, draw a line between the two points. If they make a triangle, we have to use the Pythagorean theorem. � � If we travel 8 m East and 15 m North, what is our displacement? ? 8 m 15 m

� � If we travel 8 m East and 15 m North, what is our displacement? ? 8 m 15 m A 2+B 2=C 2 82+152=C 2 64+225=C 2 289=C 2 Square root it to make the C be alone. 17=C Our displacement is 17 m.