The change in position in a given amount of time Motion The change in position in a given amount of time

Georgia Performance Standards SPS8. Students will determine relationships among force, mass, and motion. a. Calculate velocity and acceleration.

Frame of Reference The Background to which you compare the motion This changes your perspective of motion ________________ is the most common frame of reference. Examples:

Speed If the car is moving 60 mi/hr. What does that mean? It moves 60 miles every 1 hour. Speed is the _______________ covered in a certain amount of time. Speed = Distance / Time Average Speed= Total Distance/Total Time Instantaneous speed = the speed at a given point Example: look on your speedometer

Calculating Speed If Audrey rides her bike 200 meters in 45 seconds? What is her speed? ___________ 200 meters What units do you use? ______________

Calculating Distance If a dog runs at a speed of 15 m/s for 1.5 minutes (90 seconds), what distance does he travel? ____________ ? What units do you measure distance in? ______________

Calculating Time If a monkey is catapulted at a speed of 2.5 m/s, how long would it take for it to reach the target 50 meters away? 50 meters What unit would you use? ____________________

Velocity Velocity is ____________ in a given direction. Formula for velocity: Velocity = ______________ / Time (+ direction) May use the speed formula with direction for velocity. Velocity IS A VECTOR. A vector is an arrow that shows magnitude and direction. Examples of velocity: 45 km/hr East, 200 m/s Northwest How is it possible for a two cars traveling on the same road to have the same speed, but different velocities?

Calculating Net Velocity (Total Velocity) When two objects are moving in the SAME direction in relation to each other, you ADD to get the net velocity. Net Velocity (of dog in relation to ground) = ________ km/hr right 3 km/hr Bus 70 km/hr

Calculating Net Velocity (Total Velocity) When two objects are moving in OPPOSITE directions in relation to each other, you SUBTRACT to get the net velocity. Net Velocity (of dog in relation to the ground) =________ km/hr right 7 k/hr Bus 70 km/hr

Acceleration A change in __________ in a given amount of time Acceleration Formula: A = Vf – Vi -------- Time Final Velocity – Initial Velocity/ Time Question: Is acceleration affected by direction?

If a dog is walking down the sidewalk at 2 If a dog is walking down the sidewalk at 2.5 m/sec and sees a cat and speeds up to 7 m/sec in 3 seconds flat, what is his rate of acceleration? 7 m/sec 3 sec 2.5 m/sec What units are used for acceleration? ________________ Vf = 7 m/s, Vi = 2.5 m/s, Time= 3 sec 7-2.5/ 3 = ____________

Deceleration Sometimes called “negative acceleration” When calculating deceleration, use the formula for acceleration, but the answer will be negative

If a little boy is riding a skateboard at 5 m/sec and hits some gravel and slows down rapidly (in 2 seconds) to a stop. What is his rate of deceleration? 0 m/s 2 sec 5 m/sec Vf =0, Vi= 5 m/s , Time= 2 sec 0-5/2 = __________ m/s

Motion Question for you… if you are on a merry go round moving at a constant speed… which of the following would be changing… speed, direction, velocity and/or acceleration. Explain your answer.