CONVERSIONS
If you were asked how many seconds are in a day, many of you would be able to figure this out.
What would happen if you were asked the following question:
· Jeff Gordon drives his car 180 miles per hour to win the Daytona 500.
How many feet per second is that?
This question is a little harder. However with "conversions," we will be able to answer this question fairly easily.
STEP 1: Convert from miles to feet (we’ll end up with feet per hour).
STEP 2: Convert from hours to minutes (we’ll end up with feet per minute)
STEP 3: Convert from minutes to seconds (we’ll end up with feet per second)
Thus our answer is
|
180 mph = 264 ft/sec |
We could have also done that conversion in one BIG step.
· Let’s go back to the first question. How many seconds are in one day?
__________
· Bob claims he can drink a gallon of milk in an hour. How many minutes does it take him to drink a pint of milk? (How many pints are in a gallon?)
_____________________________________________________________
What is the relationship between rate of speed, time, and distance?
Rate ____ Time ______ Distance
Using that we can say: Time = ______________
Rate = _______________
Distance = ________________
We’ll use this relationship to answer the following question. Bob runs a mile in 7 minutes. He is at his friend’s house. He has to be home for dinner in 15 minutes. His house is 1000 feet away. If he starts running now, will he make it home in time?
(How long does it take Bob to run home?)
Classwork
1. If Marion Jones can run 100 yards in 10 seconds, how
many minutes would it take her to run one mile if she kept that same pace?
(3 feet = 1 yard; 5280 feet = 1 mile)
2. Rosa Moto can run a marathon (26.1 miles) in 3 hours.
a. How long does it take her to run one mile? ____________
b. How many seconds would it take her to run the 100 yard dash if she kept that same pace? _________________
3. The Sun is 149.5 million kilometers away from the
Earth. Light travels at a speed of 300 million meters per second.
How long does it take light to reach the Earth from the Sun? _______
4. Pluto is 3.6028 x 109 miles away from the Earth. The Space Shuttle travels at a rate of 2.5 x 104 feet per second. How many YEARS would it take the Space Shuttle to get to Pluto at that speed? _______