Relationships between Speed, Velocity, and Acceleration

BELL WORKFind your seat and put your stuff into the cubbie hole for your tableTake out a pen or pencilGet your Solving for Acceleration, Speed, and Velocity paper from the front lab tableRelationships between Speed, Velocity, and AccelerationMotionIt is a change in position Reference Point: the point from which all motion will be compared to.DistanceDistance: is measured as the length of a path between 2 points. Short distances are usually measured with meters and long with Kilometers.Units: meters, kilometers, centimeters, miles, inches

DisplacementDisplacement is how far an object travels from where it started.It includes the direction: ( North(N), South(S), East(E), West(W))Units: meters, kilometers, centimeters, miles, inches

Distance VS. DisplacementWatch the VideoOn your notesheet explain the differenceSpeedSPEED is the amount an object travels in a certain amount of time.Units: m/s, km/s, m/hr, km/hr, mi/hrThere are 3 different kinds of speedInstantaneous Speed: the rate of motion at any given instantConstant Speed: speed that doesn't varyAverage Speed: the total distance traveled by the total time of travel

A speedometer registers instantaneous speed Average Speed

VelocityVelocity: is the description of both speed and direction of motion.A change in velocity can result from a change in speed or direction or a change in both speed and direction.Units: m/s, km/s, m/hr, km/hr, mi/hr

Speed VS VelocityWatch the VideoOn your notesheet explain the difference

AccelerationMeans to speed up, slows down or change directionUnits: m/s2 , km/s2, m/min2 , km/min2, m/hr2 , m/hr2Positive acceleration: acceleration that is in the same direction as velocity

Negative Acceleration: acceleration that is the opposite direction as velocity (AKA deceleration)

Velocity VS AccelerationAcceleration and velocity are different quantities. Going fast does not imply accelerating quickly. The two quantities are independent of one another.Acceleration and Velocity have very different unitsRemember the formula for Acceleration!REVIEW!!

Relationships between Speed, Velocity, and AccelerationGRAPHINGReading Graphs

Distance Time GraphsNotice that time is on the x-axis and distance is on the y-axis. By reading the coordinates on the graph, you can see that the automobile reached the 50 mi position at the end of 1 h; the 100 mi position at the end of 2 h; and the 150 mi position at the end of 3 h.

Distance- Time GraphsWhen an object is moving at a steady velocity the line on the graph will move up or down in a straight line.Notice that the slope of the graph indicates the speed of the person.The faster an object travels the steeper the line.A slow speed has a gradual slope. No motion has zero slope. Constant acceleration has a curved slopeThe graph of a person at rest is a horizontal line with a slope of zerorepresenting a speed of zero. The slope of the tangent line (straight line that touches a curve in only one part) gives instantaneous speed

Acceleration on Distance-Time GraphsHeres how I used to remember if it waspositiveornegativeacceleration on a d-t graph.

Distance-Time GraphsGraph B: A person is traveling at a slow speed. As time increases, there is a small change in the position. Graph C: A person is traveling at a fast speed. As time increases, there is a greater change in the position. Graph D: A person is traveling in the opposite direction of the person in the previous graphs. As time passes, the change in position is in the opposite direction. Graph E: A person is changing speed. As time passes, the change in position is increasing for each second. Notice that a changing speed is a curve on a distance-time graph.

Graph A: A person is at rest. As time increases, there is no change in the position of the person. The person is standing still. Velocity- Time GraphsNotice that time is on the x-axis and velocity is on the y-axis. On a velocity-timegraphthe slope equalsacceleration.The "y" intercept equals theinitialvelocity.In these graphs, higher meansfasternot farther.

Velocity Time GraphsOn avelocity-timegraphstraight lines implyunchangingacceleration.curved lines implychangingacceleration.an object undergoingconstantaccelerationtraces a straight line.positive slope implies anincrease in velocity in the positive direction.negative slope implies anincrease in velocity in the negative direction.zero slope implies motion withconstantvelocity.the area under the curve equals thechangeindisplacement.

AccelerationAcceleration- Time GraphsNotice that time is on the x-axis and acceleration is on the y-axis. On a acceleration-timegraphthe slope equalsvelocity.

Acceleration- Time GraphsSlope is meaningless.When acceleration is constant, the acceleration-time curve is a horizontal line.A Line represents the motion with increasing speed when it goes upthe motion with decreasing speed when it goes down

Speeding UpSlowing DownConstant Acceleration