Presentation on theme: "Motion, Speed, and Velocity"— Presentation transcript:
1 Motion, Speed, and Velocity PhysicsMotion, Speed, and Velocity
2 SC Standards Covered PS-5.1 PS – 5.2 PS – 5.6 Explain the relationship among distance, time, direction, and the velocity of an objectPS – 5.2Use the formula v=d/t to solve problems related to average speed or velocityPS – 5.6Represent linear motion of objects on distance – time graphs
3 Motion When an object changes its position, motion has occurred. Distance- How far an object has moved.Displacement- How far an object has moved in relation to its starting point.Consider directionExample: Two runners travel along the same straight path in a straight line for 500 meters. At the end of the run their distances are the same but their displacements are different. How can this be so?
4 Speed- Distance an object travels per unit of time Relationships between speed, distance, and time:Speed = Distance/ Time = d/ tConstant Speed- speed does not change over timeAverage Speed- speed of motion when speed is changingAvg Speed = Total Distance/ Total TimeInstantaneous Speed- speed at any given moment in time (speedometer)
5 SpeedThe units for speed:meters/second (m/sec)kilometers/hour (km/hr)Speed that does not change is constant speed
6 Graphing Motion Graph distance on the y-axis and time on the x-axis Slope = rise = distance = speedrun time
7 Distance - Time GraphIf something is not moving, a horizontal line is drawn.If something starts out slow and then speeds up, its change in speed can look like this.
8 Learning Checkpoint This graph shows several stages of motion: Stage 1: 100 m in 10 sStage 2: 50 m in 10 sStage 3: 150 m in 20 sCalculate the speed as indicated by each of the colors.Calculate the average speed.What is the total distance?What is the displacement?
9 Solution Stage 1: S= d/ t 100 m/ 10 s= 10 m/s Stage 2: S= d/t Ave Speed= Tot d/ Tot t300 m/ 40 s= 7.5 m/sDistance = 300 metersDisplacement = 0 meters
10 Velocity The speed and direction of an object’s motion. 88 km / hr southwest
11 AccelerationThe change in velocityAcceleration is measured in m/sec/sec or m/sec2Formula is:(final velocity - original velocity)/time
12 Deceleration vs. Acceleration A decrease in velocity is deceleration or negative accelerationA distance-time graph for acceleration is always a curve
13 Centripetal Acceleration Acceleration directed toward the center of circular path
14 Frames of ReferenceThe object or point from which movement is determinedMovement is relative to an object that appears stationaryEarth is the most common frame of reference