Why do we use the word speedometer instead of velocimeter?
What would a vector arrow look like for someone traveling 100 km/h, West? 75 km/h, West)
Velocity…is it changing? Yes or no?
Velocity Velocity=Δdisplacement = Δx Time t = x-x₀ t-t₀ Unit: m/s →
Velocity =−4 m/5 s =−0.8sm An airplane passenger took 5 seconds to move −4 meters, (where the negative sign indicates that displacement is toward the back of the plane.) His average velocity can be written as: vavg=Δx/t =−4 m/5 s =−0.8sm
2 types of velocity Constant Speed and Constant Direction What would you have to have to have a constant velocity? Constant Speed and Constant Direction Would that be a straight line or a curved path?
2 types of velocity 2) Changing What would you have to have to have a changing velocity? Either the speed and/or direction must change
Name the 3 parts on a car that control velocity
Review 1) What is the difference between speed and velocity? a) none, they are the same b) speed is 2x faster than velocity c) speed has a direction d) velocity has a direction
Velocity Explain why we say all 3 cars are changing their velocity
Review Change the following speeds to velocity a) 22.7 m/s b) 45 mph What is the formula for velocity? v= Δx/Δt What would -3m/12 s tell you? You could be going opposite of positive (or the other direction from which you started)backing up
Explain what is happening in this picture using the words speed and velocity
If the slope of a displacement-time graph gives us _____ If the slope of a displacement-time graph gives us _____.(v= Δx/t) What would the slope of a velocity-time graph give us? ? = v/t Acceleration
Sometimes we are interested in how fast the velocity of an object is changing Acceleration Unit: m/s² or m/s S Formula: a=Δv/t = v-v₀/t
Velocity-time graph (Y-axis is important!)
What do the following lines tell us?
The speed-time graph shows how the speed of a bus changes during part of a journey.
a) OA - the speed of the bus is changing a) OA - the speed of the bus is changing. Therefore, according to the definition, the bus has an acceleration. AB - the speed does not change. The bus has a constant speed of . BC - the bus is slowing down. Its speed is changing. Therefore, according to the definition, the bus has an acceleration. CD - The bus is stationary. DE - the speed of the bus is changing. The bus has an acceleration. EF - the speed does not change. The bus has a constant speed .
A velocity-time graph can be + or -, but so can acceleration
Velocity…is it changing? Yes or no?