SOLUTION: hi, my name is jay, and i am struggling with this question. the question is: if a pitcher throws a baseball 90 miles per hour, how many seconds does it take for the ball to

Algebra ->  Equations -> SOLUTION: hi, my name is jay, and i am struggling with this question. the question is: if a pitcher throws a baseball 90 miles per hour, how many seconds does it take for the ball to       Log On


   



Question 153613This question is from textbook algebra1
: hi,
my name is jay, and i am struggling with this question. the question is:
if a pitcher throws a baseball 90 miles per hour, how many seconds does it take for the ball to reach home plate?
here's what i've tried:
time equals distance divided by speed
i divide 60.5 feet by 90 mph, and i get .6722 seconds.
Then i thought, can i really solve this equation this way? can i use feet in distance as the numerator and miles per hour in divisor. I'm not sure how to solve this.
thank you so much for your time. Jay
This question is from textbook algebra1

Found 3 solutions by stanbon, scott8148, Earlsdon:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
if a pitcher throws a baseball 90 miles per hour, how many seconds does it take for the ball to reach home plate?
-------------------------
Convert miles per hour to feet per second:
[90 miles/1 hour]
= [90 * 1 * 5280] / [1* 3600 * 1] ft./sec.
= 132 ft./sec
----------------------------
To cover 60 ft:
(60 ft/132 ft/sec) = 0.454545... seconds
==================================
Cheers,
Stan H.

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
you are right, Jay __ you need to keep the units consistent

converting miles per hour to feet per second
__ 60 seconds per minute, 60 minutes per hour __ so 60*60 or 3600 seconds per hour
__ 5280 feet in a mile
__ so feet per second equals miles per hour times 5280/3600

90 mph equals 132 fps __ so the time to the plate is 60.5/132

Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Jay, you are right to question your answer!
The answer is you must use consistent units. In other words, don't mix feet and miles or hours and seconds.
Since your problem asks "...how many seconds..." you need to convert the speed from miles per hour to feet per second.
You general approach is good!
Use: d+=+rt
Let's convert 90 mph to x ft/sec. As you know, there are 5,280 feet in one mile and there are 3600 seconds in one hour, multiply the 90 mph by 5,280 feet per mile and 1 hour by 3600 secs per hour to get:
90 mph = 132 ft/sec.
So, t+=+d%2Fr
t+=+60.5%2F132
t+=+0.45833seconds (approximately)