1 / 10

RELATING SPEED TO DISTANCE AND TIME

RELATING SPEED TO DISTANCE AND TIME. Chapter 9.5. 3 TYPES OF SPEED. 1) AVERAGE SPEED Is the total distance divided by the total time for an entire trip. Think starting and stopping (bathroom breaks) 2) INSTANTANEOUS SPEED Is the speed of an object at any instant in time.

ursala
Download Presentation

RELATING SPEED TO DISTANCE AND TIME

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. RELATING SPEED TO DISTANCE AND TIME Chapter 9.5

  2. 3 TYPES OF SPEED 1) AVERAGE SPEED • Is the total distance divided by the total time for an entire trip. • Think starting and stopping (bathroom breaks) 2) INSTANTANEOUS SPEED • Is the speed of an object at any instant in time. • Think radar gun 3) CONSTANT SPEED • Is when an object remains at the same instantaneous speed over a period of time • Think cruise control

  3. Speed (velocity) is a measure of the time required for an object to travel a certain distance. • Often measured in m/s or km/h • Distance is the amount of space between two points or objects. • Units used for distance is cm, m, km • Time is the duration between two events • Units used for time are s, min, hr • Note: We need to measure distance and time in order to determine the speed of an object.

  4. Formula for speed (or velocity): V = d (distance) t (time) • Formula for average speed: Vav = Δ d = (d2 – d1 ) Δ t (t2 - t1) (delta - Δ) – Greek Symbol meaning “a change in” d2 is final distance t2 is final time d1 is initial distance t1 is the initial time

  5. FORMULA FOR SPEED • V = d2 – d1 t2 – t1 • v = speed (velocity) – measured in m/s or km/h • d = change in distance – measured in mm, cm, m, km • t = change in time – measured in sec, min, hour, year(a)

  6. EXAMPLES • 1) Eiko skates to school, a total distance of 4.5 km. She has to slow down twice to cross busy streets, but her overall journey takes 0.62 hours. What is Eiko’s average speed during the trip? • Solution: Δd = 4.5 km , Δ t = 0.62 h, vav = ? vav = Δ d = 4.5 km = 7.3 km / h Δ t 0.62 h Eiko’s average skating speed is 7.3 km/h.

  7. Imagine that you are riding on the Cariboo Dayliner train and you see a sign that reads 120 km. After seeing several signs like this, you decide to time between two of the signs which are 10 km apart. The elapsed time is recorded at 390.6 s. What is the speed of the train in km/h? • SOLUTION: d = 10 km , t = 390.6 s, v = ? t = 390.6 s = 0.1085 h v = d = 10 km = 92 km/h 3600 s t 0.1085 h The train is traveling at 92 km/h.

  8. 3) Same information of 2 but the question asked for m/s instead of km/h. • SOLUTION: d = 10 km, t = 390.6 s , v = ? d = 10 km x 1000 m = 10 000 m v = d = 10000 m = 25.60 m/s 1 km t 390.6 s The train is traveling at 25.60 m/s.

  9. 4) Kira is trying to predict the time required to ride her bike to the nearby beach. She knows that the distance is 45 km and from other trips, she can average about 20 km/h. How long will her trip take? • SOLUTION: Δ d = 45 km, vav = 20 km/h, Δ t = ? Rearrange Formula for t. Δ t = Δ d = 45 km = 2.3 h vav 20 km/h Kira should be able t make the trip in 2.3 h.

  10. PRACTICE • Do the 9.5 Supplemental practice problems or 10 Questions Handout • Text page 358 • Questions #3,4,8,9,10a, 11ab • Handout 9.5b , 9.5 d

More Related