Math Problem Statement

A car travels along a straight road, heading east for one hour, then traveling for 30 min on another road that leads northeast. If the car has maintained a constant speed of 48 mi/h, how far is it from its starting position? (Round your answer to one decimal place.)

Solution

To solve this problem, we need to break down the car's motion into two components: one for the eastward travel and another for the northeastward travel.

Step 1: Calculate the distance for each leg of the journey.

  • Eastward Travel: The car travels east for 1 hour at a speed of 48 miles per hour. The distance covered during this part of the trip is: Distance east=48mi/h×1hour=48miles.\text{Distance east} = 48 \, \text{mi/h} \times 1 \, \text{hour} = 48 \, \text{miles}.

  • Northeastward Travel: The car then travels northeast for 30 minutes (which is 0.5 hours) at the same speed of 48 miles per hour. The distance covered during this part is: Distance northeast=48mi/h×0.5hours=24miles.\text{Distance northeast} = 48 \, \text{mi/h} \times 0.5 \, \text{hours} = 24 \, \text{miles}. Since the direction is northeast, the motion is at a 45° angle to the eastward direction. Therefore, the eastward and northward components of this distance are the same.

    The horizontal (eastward) and vertical (northward) components of the 24 miles are: East component=24×cos(45)=24×2224×0.7071=16.97miles.\text{East component} = 24 \times \cos(45^\circ) = 24 \times \frac{\sqrt{2}}{2} \approx 24 \times 0.7071 = 16.97 \, \text{miles}. North component=24×sin(45)=24×2216.97miles.\text{North component} = 24 \times \sin(45^\circ) = 24 \times \frac{\sqrt{2}}{2} \approx 16.97 \, \text{miles}.

Step 2: Find the total eastward displacement.

The total eastward displacement is the sum of the eastward distances from both parts of the trip: Total eastward distance=48+16.97=64.97miles.\text{Total eastward distance} = 48 + 16.97 = 64.97 \, \text{miles}.

Step 3: Find the total northward displacement.

The total northward displacement comes only from the northeastward portion of the trip: Total northward distance=16.97miles.\text{Total northward distance} = 16.97 \, \text{miles}.

Step 4: Calculate the total distance from the starting position.

Now we can use the Pythagorean theorem to find the straight-line distance (the resultant displacement) from the starting position. This is the hypotenuse of a right triangle with legs 64.97 miles (eastward displacement) and 16.97 miles (northward displacement): Distance from starting position=(64.97)2+(16.97)2\text{Distance from starting position} = \sqrt{(64.97)^2 + (16.97)^2} =4228.57+288.94= \sqrt{4228.57 + 288.94} =4517.5167.3miles.= \sqrt{4517.51} \approx 67.3 \, \text{miles}.

Final Answer:

The car is approximately 67.3 miles from its starting position.


Would you like more details or have any further questions?

Here are some related questions:

  1. How can the concept of vector components be used to solve similar problems in physics?
  2. What would the result be if the car had traveled at a different speed, say 60 mi/h?
  3. How does the Pythagorean theorem apply to real-world navigation problems?
  4. How do you calculate displacements in problems involving circular motion?
  5. What would be the effect if the car traveled for a longer time in the northeast direction?

Tip: Always break complex motion into horizontal and vertical components to simplify the calculations.

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Math Problem Analysis

Mathematical Concepts

Vector Components
Trigonometry
Pythagorean Theorem

Formulas

Distance = Speed × Time
Vector Components: x = r × cos(θ), y = r × sin(θ)
Pythagorean Theorem: d = sqrt(x^2 + y^2)

Theorems

Pythagorean Theorem
Trigonometric Ratios

Suitable Grade Level

Grades 9-12