Acceleration is a change in velocity by Changing speed: ▪ Starting ▪ Stopping ▪ Speeding up...
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Transcript of Acceleration is a change in velocity by Changing speed: ▪ Starting ▪ Stopping ▪ Speeding up...
AccelerationAcceleration is a change in
velocity by Changing speed:
▪ Starting
▪ Stopping
▪ Speeding up
▪ Slowing down Or changing direction
Acceleration
Acceleration can be positive or negative
Speeding Up – Positive acceleration (+)
Slowing Down – Negative acceleration (-)
Units – measured in m/s2
Acceleration is caused by unbalanced forces
Calculating Acceleration:
Final Speed – Initial Speed
Time
Speed A way to describe motion.
Average speed - Rate of motion calculated by dividing the distance traveled by the amount of time it takes to travel that distance
Constant speed - Speed that does not change
Instantaneous speed - Speed of an object at any given time
Units: Measured in m/s
Speed is calculated by dividing distance by time.
What is the formula for calculating speed?
Distance Time
Speed =
Calculating SpeedGiven Distance & Time
Divide Distance by Time
Distance ÷ Time = Speed
Speed = Distance ÷ Time
Calculating DistanceGiven Speed & Time
Multiply Speed and Time
Distance = Speed X Time
Speed X Time = Distance
Calculating TimeGiven Distance and Speed
Divide Distance by Time
Distance ÷ Speed = Time
Time = Distance ÷ Speed
Calculate this Speed
A football field is about 100 m long. If it takes a person 20 seconds to run its length, how fast was the football player running?
A football field is about 100 m long. If it takes a person 20 seconds to run its length, how fast was the football player running?
Speed = Distance ÷ Time
Speed = 100 m ÷ 20 s
Speed = 5 m/s
Remember to include
the UNITS!!
Calculate this Speed:
Velocity Velocity is speed with direction Calculating velocity is the same as
calculating speed (distance/time). The difference is that velocity is what
physicists call a vector.
There must be direction. Speed = 3 m/s Velocity = 3 m/s, heading northeast
Velocity = Final Distance – Initial Distance Final Time – Initial TimeVelocity = Final Distance – Initial Distance Final Time – Initial Time
Distinguish between Speed and Velocity
Speed describes distance and time
Velocity describes distance, time, and direction
You can say the top speed of an airplane is 300 kilometers per hour (kph). But its velocity is 300 kph in a northeast direction.
Let’s PracticeWhich of the following sentences contain an example of velocity and which contain an example of speed?
A. Five seconds into the launch, the rocket was shooting upward at 5000 meters per second.
B. Cheetahs can run at 70 miles per hour.
C. Moving at five kilometers per hour, it will take us eight hours to get to the base camp.
D. The car covered 500 kilometers in the first 10 hours of its northward journey.
E. Roger Bannister was the first person to run one mile in less than four minutes.
Velocity
Velocity
Speed
Speed
Speed
Summarizing Podcast