Math Problem Statement

Jam terdiri dari beberapa jarum, seperti jarum jam dan jarum menit. Panjang jarum menit sebuah jam adalah 14 cm. Jika jarum telah bergerak selama 30 menit, panjang lintasan yang dilalui ujung jarum jam tersebut adalah ... cm

Solution

Let's solve this problem step by step.

The question is about a clock's minute hand that has moved for 30 minutes, and we need to find the distance traveled by the tip of the minute hand in centimeters.

Given Information

  1. The length of the minute hand is 14cm14 \, \text{cm}.
  2. The minute hand moves for 30 minutes.

Solution

  1. Determine the Angle Covered: In 60 minutes, the minute hand completes a full circle, which is 360360^\circ.

    • Since 30 minutes is half of 60 minutes, the minute hand will cover half of 360360^\circ, which is 180180^\circ.
  2. Calculate the Arc Length:

    • The arc length LL for an angle θ\theta in a circle of radius rr is given by: L=θ360×2πrL = \frac{\theta}{360^\circ} \times 2 \pi r
    • Here, θ=180\theta = 180^\circ and r=14cmr = 14 \, \text{cm}.
  3. Substitute the Values: L=180360×2×π×14L = \frac{180}{360} \times 2 \times \pi \times 14 Simplifying this: L=12×2π×14L = \frac{1}{2} \times 2 \pi \times 14 L=π×14L = \pi \times 14 L=14πcmL = 14 \pi \, \text{cm}

  4. Approximate the Answer (using π3.14\pi \approx 3.14): L14×3.14L \approx 14 \times 3.14 L43.96cmL \approx 43.96 \, \text{cm}

Final Answer

The distance traveled by the tip of the minute hand is approximately 43.96 cm.

Would you like further details on any part of this solution, or do you have any additional questions?

Here are some related questions to expand your understanding:

  1. How would the answer change if the minute hand length was different?
  2. What would be the distance covered if the minute hand moved for 15 minutes?
  3. How can we generalize this formula for any movement of the minute hand?
  4. What if we were calculating the path of the hour hand instead?
  5. How does the concept of angular displacement apply here?

Tip: Remember that a minute hand covers 66^\circ per minute because 360360^\circ is divided among 60 minutes.

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Math Problem Analysis

Mathematical Concepts

Geometry
Circle
Arc Length

Formulas

Arc length formula L = (θ/360) × 2πr

Theorems

Central Angle Theorem

Suitable Grade Level

Grades 7-9