170 likes | 339 Views
Acceleration, Speed, and Velocity. Acceleration. Acceleration 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 (+)
E N D
Acceleration • Acceleration 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
What is the formula for calculating speed? Speed is calculated by dividing distance by time. 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?
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? Speed = Distance ÷ Time Speed = 100 m ÷ 20 s Speed = 5 m/s Remember to include the UNITS!!
Velocity= Final Distance – Initial Distance Final Time – Initial Time Velocity= Final Distance – Initial Distance Final Time – Initial Time 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
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 Practice Which of the following sentences contain an example of velocity and which contain an example of speed? • Five seconds into the launch, the rocket was shooting upward at 5000 meters per second. • Cheetahs can run at 70 miles per hour. • Moving at five kilometers per hour, it will take us eight hours to get to the base camp. • The car covered 500 kilometers in the first 10 hours of its northward journey. • Roger Bannister was the first person to run one mile in less than four minutes. • Velocity • Speed • Speed • Velocity • Speed
Summarizing • Podcast
Velocity Speed Time m/s Direction m/s north Distance • Time • m/s • m/s north • m/s2 • Distance • Direction m/s2 Acceleration