Velocity + Acceleration. SI units SI units needed Time = seconds (s) Other common units are the...
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Transcript of Velocity + Acceleration. SI units SI units needed Time = seconds (s) Other common units are the...
![Page 1: Velocity + Acceleration. SI units SI units needed Time = seconds (s) Other common units are the minute, hour, microsecond and nanosecond Distance.](https://reader033.fdocuments.us/reader033/viewer/2022051215/56649ea05503460f94ba28d3/html5/thumbnails/1.jpg)
Velocity + Acceleration
![Page 2: Velocity + Acceleration. SI units SI units needed Time = seconds (s) Other common units are the minute, hour, microsecond and nanosecond Distance.](https://reader033.fdocuments.us/reader033/viewer/2022051215/56649ea05503460f94ba28d3/html5/thumbnails/2.jpg)
SI units
SI units needed Time = seconds (s) Other common units are the minute,
hour, microsecond and nanosecond Distance = meters (m) Other common units are the
centimeter, millimeter, kilometer, nanometer and picometer
![Page 3: Velocity + Acceleration. SI units SI units needed Time = seconds (s) Other common units are the minute, hour, microsecond and nanosecond Distance.](https://reader033.fdocuments.us/reader033/viewer/2022051215/56649ea05503460f94ba28d3/html5/thumbnails/3.jpg)
Distance vs. Displacement
Distance is equal to the total amount of space something moved
Displacement is the space moved from the initial position.
![Page 4: Velocity + Acceleration. SI units SI units needed Time = seconds (s) Other common units are the minute, hour, microsecond and nanosecond Distance.](https://reader033.fdocuments.us/reader033/viewer/2022051215/56649ea05503460f94ba28d3/html5/thumbnails/4.jpg)
Speed
Lunar recession = 1.3x10-9 Snail = 1x10-6 Man = 10m/s Cheetah = 30 m/s Sound at S.L. = 340 m/s M-16 bullet = 975m/s SR-71 Blackbird = 981m/s Apollo =11082 m/s *record Earth orbit = 29800 m/s Solar system orbit = 2x105
m/s Light = 3x108 m/s
Speed: Rate of change in position or how fast something is going
Given in distance per unit of time
m/s km/h mph In physics magnitude
of velocity vector Average speed – total
distance/ total time 95 miles in 1:20 What is
the average speed?
![Page 5: Velocity + Acceleration. SI units SI units needed Time = seconds (s) Other common units are the minute, hour, microsecond and nanosecond Distance.](https://reader033.fdocuments.us/reader033/viewer/2022051215/56649ea05503460f94ba28d3/html5/thumbnails/5.jpg)
Instant speed
Instantaneous speed – speed at an exact moment in time – speedometer in a car
Constant speed – objects with no variation in speed – vehicles rarely travel at constant speeds
![Page 6: Velocity + Acceleration. SI units SI units needed Time = seconds (s) Other common units are the minute, hour, microsecond and nanosecond Distance.](https://reader033.fdocuments.us/reader033/viewer/2022051215/56649ea05503460f94ba28d3/html5/thumbnails/6.jpg)
Velocity
Calculating speed: s = d/t
Velocity : speed and direction of something
V=d/t 2 people traveling at
60 km/h in different directions don’t have the same velocity
Thought Question: Does constant speed necessarily imply constant velocity?
![Page 7: Velocity + Acceleration. SI units SI units needed Time = seconds (s) Other common units are the minute, hour, microsecond and nanosecond Distance.](https://reader033.fdocuments.us/reader033/viewer/2022051215/56649ea05503460f94ba28d3/html5/thumbnails/7.jpg)
Calcultions
You travel from Mandan to Fargo in your ‘87 Oldsmobuick, the trip of 210 miles takes you 2 hours 40 minutes. What was your average velocity.
How long would it take you to travel to Minneapolis 66O km if you drove at 115 km/h.
How far is the nearest star if it takes you 2.7 years traveling at the speed of light to reach it.
![Page 8: Velocity + Acceleration. SI units SI units needed Time = seconds (s) Other common units are the minute, hour, microsecond and nanosecond Distance.](https://reader033.fdocuments.us/reader033/viewer/2022051215/56649ea05503460f94ba28d3/html5/thumbnails/8.jpg)
Problems
Speed and velocity are often used interchangeably but it is important to remember that velocity implies a direction of travel. This is especially important when it comes to the forces and energy that cause changes in motion.
![Page 9: Velocity + Acceleration. SI units SI units needed Time = seconds (s) Other common units are the minute, hour, microsecond and nanosecond Distance.](https://reader033.fdocuments.us/reader033/viewer/2022051215/56649ea05503460f94ba28d3/html5/thumbnails/9.jpg)
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![Page 10: Velocity + Acceleration. SI units SI units needed Time = seconds (s) Other common units are the minute, hour, microsecond and nanosecond Distance.](https://reader033.fdocuments.us/reader033/viewer/2022051215/56649ea05503460f94ba28d3/html5/thumbnails/10.jpg)
Graphing
http://webphysics.davidson.edu/physlet_resources/bu_semester1/c2_twocars_graphs.html
What do the slopes of each graph represent?
![Page 11: Velocity + Acceleration. SI units SI units needed Time = seconds (s) Other common units are the minute, hour, microsecond and nanosecond Distance.](https://reader033.fdocuments.us/reader033/viewer/2022051215/56649ea05503460f94ba28d3/html5/thumbnails/11.jpg)
Acceleration
Acceleration is the change in velocity over time. Constant speed does not imply constant velocity
Positive acceleration- Acceleration in the same direction as velocity
Negative acceleration- acceleration in the opposite direction of velocity
![Page 12: Velocity + Acceleration. SI units SI units needed Time = seconds (s) Other common units are the minute, hour, microsecond and nanosecond Distance.](https://reader033.fdocuments.us/reader033/viewer/2022051215/56649ea05503460f94ba28d3/html5/thumbnails/12.jpg)
Acceleration
How many ways can you accelerate in your car?
1. 2. 3. So your car has 3
accelerators Calculate acceleration
:
![Page 13: Velocity + Acceleration. SI units SI units needed Time = seconds (s) Other common units are the minute, hour, microsecond and nanosecond Distance.](https://reader033.fdocuments.us/reader033/viewer/2022051215/56649ea05503460f94ba28d3/html5/thumbnails/13.jpg)
Acceleration formulas
To calculate acceleration Calculate the change in velocity and
divide by the change in time. a =( final velocity – initial velocity) /
time for the change to take place a= vf – vi/t or a = v /t
![Page 14: Velocity + Acceleration. SI units SI units needed Time = seconds (s) Other common units are the minute, hour, microsecond and nanosecond Distance.](https://reader033.fdocuments.us/reader033/viewer/2022051215/56649ea05503460f94ba28d3/html5/thumbnails/14.jpg)
Acceleration Problem
If you drop a penny off of the Empire State Building and it reaches a speed of 29.4m/s after 3 seconds, what is its average acceleration?
How long would the penny have to fall to reach a speed of 100m/s?