SpeedSpeed

What is time?What is time?

A particular momentA particular moment– 10:25 and 15 secs10:25 and 15 secs

An interval of timeAn interval of time– 7pm to 7am7pm to 7am

TimeTime Measured in hours, Measured in hours,

minutes, days, years minutes, days, years and secondsand seconds

Metric only in scienceMetric only in science

Always a Always a numbernumber and and a a unitunit -25 secs -25 secs

What is distance?What is distance? How far from one point How far from one point

to anotherto another

Unit of lengthUnit of length

Metric only in scienceMetric only in science

Always a Always a numbernumber and and a a unitunit – 25 m – 25 m

SpeedSpeed

Measure of how quickly an object moves from one place to Measure of how quickly an object moves from one place to anotheranother

An object that is not moving has a speed of zero - 0 m/sAn object that is not moving has a speed of zero - 0 m/s Distance traveled divided by the time takenDistance traveled divided by the time taken

– 90 miles in 1.5 hours = 90mi /1.5 h = 60 mph90 miles in 1.5 hours = 90mi /1.5 h = 60 mph

VelocityVelocity

Speed of the object and the direction of its Speed of the object and the direction of its motionmotion

SpeedSpeed Speed = vSpeed = v

– v is for velocity (speed with direction v is for velocity (speed with direction added, traveled 75 mph south)added, traveled 75 mph south)

Distance = dDistance = d Time = tTime = t

ProblemsProblems

A nascar driver has a car that is one of the A nascar driver has a car that is one of the fastest on the circuit. If it travels 600 miles fastest on the circuit. If it travels 600 miles in 4 hours, what is his cruising speed?in 4 hours, what is his cruising speed?

1.1. v = d/tv = d/t

2.2. v = ? v = ?

d = 600 milesd = 600 miles

t = 4 hrst = 4 hrs

3. v = 600 mi/4 hrs3. v = 600 mi/4 hrs

4. v = 150 mi/hr4. v = 150 mi/hr

The fastest car on Earth, a German-made The fastest car on Earth, a German-made Thrust Thrust SSCSSC, would win every Nascar race in America. If , would win every Nascar race in America. If it takes 0.5 hours (30 minutes) to travel 380 it takes 0.5 hours (30 minutes) to travel 380 miles, what is its speed?miles, what is its speed?

1.1. v = d/tv = d/t2.2. v = ?v = ?

d = 380 milesd = 380 milest = 0.5 hrst = 0.5 hrs

3. v = 380 mi/ 0.5 hr3. v = 380 mi/ 0.5 hr4. v = 760 mi/h (mph)4. v = 760 mi/h (mph)

The fastest train on Earth, the The fastest train on Earth, the TGV TGV from France, can from France, can travel at faster speeds than trains in the United travel at faster speeds than trains in the United States. During a speed test, the train traveled States. During a speed test, the train traveled 800 miles in 2.5 hours. What is its speed?800 miles in 2.5 hours. What is its speed?

1.1. v = d/tv = d/t2.2. v = ?v = ?

d = 800 milesd = 800 miles t = 2.5 hrst = 2.5 hrs

3. 3. v = 800 mi/ 2.5 hrv = 800 mi/ 2.5 hr4.4. v = 320 mi/h (mph)v = 320 mi/h (mph)

Spirit of AustraliaSpirit of Australia, a hydroplane boat, made speed , a hydroplane boat, made speed records by traveling 239 miles in 0.75records by traveling 239 miles in 0.75

hours (45 minutes). What is its record-breaking hours (45 minutes). What is its record-breaking speed?speed?

1.1. v = d/tv = d/t

2.2. v =?v =?

d =239 milesd =239 miles

t = 0.75 hrst = 0.75 hrs

3.3. v = 239 mi/ 0.75 hrv = 239 mi/ 0.75 hr

4.4. v = 318.67 mi/h (mph)v = 318.67 mi/h (mph)

How much time does it take for a bird How much time does it take for a bird flying at a speed of 45 miles per hour to flying at a speed of 45 miles per hour to travel a distance of 1,800 miles?travel a distance of 1,800 miles?

1.1. t = d/vt = d/v2.2. t = ?t = ?

d = 1800 milesd = 1800 milesv = 45 mphv = 45 mph

3.3. t = 1800 mi /45 mi/hrt = 1800 mi /45 mi/hr4.4. v = 40 hrs v = 40 hrs

A cheetah runs at 60 mph for a distance of 0.5 miles. A cheetah runs at 60 mph for a distance of 0.5 miles. How long does this take? Change answer to seconds.How long does this take? Change answer to seconds.

1.1. t = d/vt = d/v2.2. t = ?t = ?

d = 0.5 milesd = 0.5 milesv = 60 mphv = 60 mph

3.3. t = 0.5 mi/ 60mpht = 0.5 mi/ 60mph4.4. t = 0.008 hrt = 0.008 hr

0.008 hr x 0.008 hr x 60 min60 min X X 60 sec60 sec = 28.8 secs = 28.8 secs 1hr1hr 1 min1 min

A comet is cruising through the solar system at a A comet is cruising through the solar system at a speed of 50,000 kilometers per hour for 4 hours speed of 50,000 kilometers per hour for 4 hours time. What is the total distance traveled by the time. What is the total distance traveled by the comet during this time?comet during this time?

1.1. d = vtd = vt

2.2. d = ?d = ?

v = 50,000 km/hv = 50,000 km/h

t = 4 hrst = 4 hrs

3.3. d = 50,000 km/h X 4 hrsd = 50,000 km/h X 4 hrs

4.4. d = 200,000 kmd = 200,000 km

A runner runs 6.9 mph for 54 minutes. What distance did A runner runs 6.9 mph for 54 minutes. What distance did the runner travel? the runner travel?

1.1. d = vtd = vt2.2. d = ?d = ?

v = 6.9 mphv = 6.9 mpht = 54 minutest = 54 minutes

3.3. d = 6.9 mph X 54 mind = 6.9 mph X 54 min4.4. d = 372.6 mph/min (Does this make sense)d = 372.6 mph/min (Does this make sense)

Must change minutes to hoursMust change minutes to hours– 54 min X 54 min X 1 hour1 hour = 0.9 hr = 0.9 hr

60 min60 min d = 6.9 mph X 0.9 hr = 6.2 milesd = 6.9 mph X 0.9 hr = 6.2 miles

Time vs distance GraphTime vs distance Graph

Shows distance traveled in relation to time traveledShows distance traveled in relation to time traveled Line sloping upward – steady speed Line sloping upward – steady speed Change in upward slope = changing speedChange in upward slope = changing speed

– Steeper = faster Steeper = faster Flat line – no motionFlat line – no motion Downward slope – returning to startDownward slope – returning to start

Time vs distance GraphTime vs distance Graph

Slope of a distance/ time graph or a position/time graph will Slope of a distance/ time graph or a position/time graph will tell us the speedtell us the speed

Slope = rise/runSlope = rise/run Slope = 60 miles/2 hrsSlope = 60 miles/2 hrs Speed = 30 miles/hrSpeed = 30 miles/hr

Average SpeedAverage Speed

Average of all speeds over time traveledAverage of all speeds over time traveled Speed may not be constantSpeed may not be constant Distance to San Antonio, Texas Distance to San Antonio, Texas

– 1000 miles1000 miles Time traveledTime traveled

– 15 hours15 hours Average speed equalsAverage speed equals

– 66.66 mph66.66 mph

Instantaneous SpeedInstantaneous Speed

Speed at a certain moment in timeSpeed at a certain moment in time