Presentation on theme: "What is Motion? Motion: A change in position of an object compared to a reference point Motion involves all of the following: You fill in the blank!"— Presentation transcript:
What is Motion? Motion: A change in position of an object compared to a reference point Motion involves all of the following: You fill in the blank!
Definition of Motion Event that involves a change in the position or location of something.
Motion is Relative Relative – it is described or compared to a REFERENCE POINT g7_relmotion.html e.php?rid=937&rurlid=894 e.php?rid=937&rurlid=894 Example: Are you moving at this moment? If yes, then how are you moving? How does your movement look to another person? (Can they tell you are moving?)
Displacement vs Distance Displacement - the distance and direction of an object’s change in position from its starting point Distance – how far something moves Fgjflgjkfdlgjflgjkdflg vxcvxcbcvbcvbcj
Displacement vs Distance Displacement - the distance and direction of an object’s change in position from its starting point Distance – how far something moves
What is the Displacement? Problem - A physics teacher walks 4 meters east, 2 meters south, 4 meters west, and 2 meters north. What is the total displacement of the teacher? What is the total distanced walked by the teacher?
And the answer is... Displacement = 0 m - The teacher has returned to the starting point. Distance = 12 meters The distance is 12 meters but the displacement is zero. The teacher has “covered 12 meters on the ground”, yet when he is finished walking, he is not walking out of place.
Types of Motion Uniform motion - constant speed in a straight line Accelerated motion – motion that is changing in speed or direction Circular motion - speed is constant but the direction of motion is changing continuously
What is Motion? Speed The rate of change in position Speed = distance ÷ time or Speed = distance time
Speed Types of Speed Average Speed Instantaneous Speed Constant Speed
Speed Average Speed Comparison of time and distance – Distance traveled per unit time – Distance is referring to "how much ground an object has covered" during the time it was in motion. S = d / t S = d / t T = d / s T = d / s D = s x t D = s x t
Speed Instantaneous Speed Speed at any instant
Speed Constant Speed Speed that does not change – Instantaneous speed that does not change – Example: After setting cruise control on a car, your speed at any point will be the same until you turn off the cruise control.
What is Motion? Velocity Speed plus direction Example: 50 km/hour north
Velocity Speed AND direction -- Velocity must include a speed and a direction. Displacement is "how far out of place an object is because of its motion”. Displacement is the object's change in position.
What is Motion? Acceleration The rate of change in velocity Positive acceleration = speeding up Negative acceleration = slowing down (decelerate) Acceleration = V final – V initial Time or Acceleration = ∆Velocity Time
Acceleration "the rate at which an object changes its velocity." An object is accelerating if it is changing its velocity.
Acceleration A change in velocity – Speeding up Positive acceleration – Slowing down Negative acceleration Deceleration – Changing direction
The Direction of Acceleration Acceleration will always have a direction associated with it. The direction of acceleration depends on two things: whether the object is speeding up or slowing down whether the object is moving in the + or - direction
Circular Motion: Continuous Acceleration An object traveling in a circular motion is always changing its direction. Therefore, its velocity is always changing, so it is accelerating. This is known as centripetal acceleration.
200m/40s = 5 m/s 2 km/1000s = km/s or 2 m/s 100 m/10 m/s = 10s 50 m/s x 20s = 1000 m 20,000 m/ 40 m/s = 500 s
10m/20s = 0.5 m/s 40 m 40m/40s = 1m/s 25m/10s = 2.5 m/s Steepest line
10m/s 2 / 5 s = 2 m/s 10m/s 2 x 12s = 120 m/s 10m/s / 2m/s = 5 s 4000m/s /2s = 2000m/s 2
40m/s x 10s = 4 m/s 2 20m/s x 10s = 2 m/s 2 60m/s x 20s = 3 m/s 2 4dfdsfsdfsdfsafsdfdsfsfsfdsffsdfsdfsdfsdfsdfsdfsfdsfsfasdfs
Motion Graphs Time – Distance Graphs
Motion Graph # 1 Straight, Flat Line As time passes, there is no change in distance; no motion
Motion Graph # 2 Straight, Increasing Line As time passes, distance increases The change in distance is constant – no stopping & starting
Motion Graph # 3 Straight, Decreasing Line As time passes, distance decreases The change in distance is constant
Motion Graph # 4 Changing Line A changing line means changing distance Distance increases then doesn’t change then decreases
Representing Motion in Graphs Distance – Time Velocity - Time
Describing a Distance - Time Graph
Describing a Velocity - Time Graph
Speed, Distance, Time Formulas
Calculating Speed Given Distance & Time Divide Distance by Time Distance ÷ Time = Speed Speed = Distance ÷ Time Divide Distance by Time Distance ÷ Time = Speed Speed = Distance ÷ Time
Calculating Distance Given Speed & Time Multiply Speed and Time Distance = Speed X Time Speed X Time = Distance
Calculating Time Given Distance and Speed Divide Distance by Speed Distance ÷ Speed = Time Time = Distance ÷ Speed