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Zorluk: OrtaRelative Motion and Catch-Up Scenarios

A military transport convoy departs from a base and travels on a straight route at a constant speed of 3030 mph. Exactly 1515 minutes later, a tactical vehicle is dispatched along the same route to deliver updated orders, traveling at a constant speed of 4545 mph. How many minutes will it take for the tactical vehicle to catch up to the convoy from the time the tactical vehicle departs?

  1. A
    6
  2. B
    60
  3. 30Cevap
  4. D
    300

Cevap

30
The correct answer accurately calculates the 7.57.5-mile head start distance (30 mph×0.25 hours30 \text{ mph} \times 0.25 \text{ hours}) and divides it by the 1515 mph relative speed (45 mph−30 mph45 \text{ mph} - 30 \text{ mph}) to find a catch-up time of 0.50.5 hours, which equals 3030 minutes.

Adım Adım Çözüm

1
Convert the convoy's head start time from minutes to hours.
15 minutes=0.25 hours15 \text{ minutes} = 0.25 \text{ hours}.
Vehicle speeds are given in miles per hour (mph), so the time must be converted to hours for unit consistency.
2
Calculate the distance the convoy traveled during its head start.
30 mph×0.25 hours=7.5 miles30 \text{ mph} \times 0.25 \text{ hours} = 7.5 \text{ miles}.
This establishes the initial distance gap that the tactical vehicle needs to close.
3
Determine the relative catch-up speed of the tactical vehicle.
45 mph−30 mph=15 mph45 \text{ mph} - 30 \text{ mph} = 15 \text{ mph}.
Because the vehicles are traveling in the same direction, you subtract the slower speed from the faster speed to find the rate at which the gap is closing.
4
Calculate the time required to close the gap in hours.
7.5 miles÷15 mph=0.5 hours7.5 \text{ miles} \div 15 \text{ mph} = 0.5 \text{ hours}.
Time equals distance divided by rate (t=drt = \frac{d}{r}).
5
Convert the catch-up time back to minutes.
0.5 hours×60 minutes/hour=30 minutes0.5 \text{ hours} \times 60 \text{ minutes/hour} = 30 \text{ minutes}.
The question specifically asks for the time in minutes.

Anahtar Kavram

Catch-up scenarios require calculating the initial distance gap and dividing it by the relative speed (the difference in speeds) between the two moving objects.
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