Velocity and Acceleration :
Velocity and Acceleration Motion :
Motion Reference point- stationary object that helps you determine how far something moved
Distance- how far an object moves
Unit- meter (m)
Displacement- distance and direction of an object’s change in position from the starting point
Speed – distance traveled per unit time
s = d/t
Speed = distance / time
Unit- m/s Speed :
Speed Average speed- total distance divided by total time Speed :
Speed Instantaneous speed- speed at that moment
Like your speedometer
Constant speed- speed doesn’t change
Distance-time graph- has time on the x-axis and distance on the y-axis
Slope is speed
Steeper line = faster
Flat line = stopped
Negative slope = moving backwards Distance- Time Graph :
Distance- Time Graph Velocity :
Velocity If you know that a hurricane is moving at 20 km/h, and it is 100 km away from you, do you need to be concerned?
Maybe- you can’t tell- it might be headed toward you or away from you!!
Velocity – Speed and direction
Car one is headed east at 50 mph. Car two is headed west at 50 mph. Do they have the same speed? The same velocity?
Speed – yes
Velocity - no Relative Motion :
Relative Motion Are you moving if you are sitting 100% still in your chair??
YES! The earth is moving and you are on the earth, so you are moving relative to the other planets, the sun, etc.
NO! Relative to the floor, you are not moving
It all depends on your frame of reference
Relative motion – motion depends on your frame of reference
http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=140 Acceleration :
Acceleration Acceleration- rate of change in velocity
Occurs when speed or direction changes
Negative acceleration- when something slows down
Positive acceleration- when something speeds up
Change in velocity / change in time = acceleration
Acceleration = Force / mass
Units m/s2
Acceleration due to gravity = 9.8 m/s2 Velocity- Time Graph :
Velocity- Time Graph Velocity- Time graph :
Velocity- Time graph Slope = acceleration
Flat slope = constant speed
Positive slope = sleeping up
Negative slope = slowing down Design your own experiment :
Design your own experiment Choose one option:
You have 2 toy cars. Which one will have the greatest velocity with the same force applied to both?
You have 2 toy cars. Which one will have the greatest acceleration with the same force applied to both?
Or do both for extra credit!