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Julie drives 100 mi to Grandmother’s house. On the way to Grandmother’s, Julie drives half the distance at 38.0 mph and half the distance at
Question
Julie drives 100 mi to Grandmother’s house. On the way to Grandmother’s, Julie drives half the distance at 38.0 mph and half the distance at 62.0 mph. On her return trip, she drives half the time at 38.0 mph and half the time at 62.0 mph.A) What is Julie’s average speed on the way to grandmother’s house?B) What is her average speed in the return trip?
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Physics
3 years
2021-08-05T20:34:23+00:00
2021-08-05T20:34:23+00:00 2 Answers
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Answers ( )
Answer:
46.95 mph
50 mph
Explanation:
first, we start by finding the average speed. The average speed if given by the relation
Average Speed = Total distance / Total Time
from the question, we know that
total distance is 100 mi
total time is time of the first distance + time of the second distance
t = (50mi / 38) + (50mi / 62)
t = 1.32 + 0.81
t = 2.13 hrs
Then, the average speed going to grandmothers house will be
Speed = 100mi / 2.13 hrs
Speed = 46.95 mph
on her return trip
speed on the first distance * half the time + speed on the second distance * half the time
x = V1 * t/2 + V2 * t/2
100 = 38 * t/2 + 62 * t/2
100 = 100 * t/2
t/2 = 100/100
t/2 = 1
t = 2 hrs
The average speed then will be, = 100 mi / 2 hrs = 50mph
Answer:
A.46.7mph
B.50mph
Explanation:
We know that from the data given
Julie drove 50 miles at a speed of 38 mph, and another 50 miles for 62mph. Thus , for the first 50 miles, she drove for the following time
T1= distance/speed
====> 50/38= 1.3hrs
the next 50 miles, she drove for
T2= 50/62
= 0.8hrs
So average speed is
Totaldistance/ total time
100/2.1
= 46.7mph
B. Because the time she used driving at 35 mph is the same amount of time she used driving at 65 mph, the average speed is just the average of the two speeds given which is
(50+50)/2 = 50mph
Explanation: