Math Problem Statement

An object moves along a horizontal axis with velocity v = t - 5. What is the total distance the object travels between t = 0 and t = 6?

Solution

To solve for the total distance traveled by an object moving with velocity v=t5v = t - 5 between t=0t = 0 and t=6t = 6, we need to integrate the absolute value of the velocity function over this interval.

The velocity function is v(t)=t5v(t) = t - 5. The object changes direction when the velocity is zero, which happens when t5=0t - 5 = 0 or t=5t = 5.

We will split the integral into two parts: from t=0t = 0 to t=5t = 5, and from t=5t = 5 to t=6t = 6.

  1. From t=0t = 0 to t=5t = 5: The velocity v(t)=t5v(t) = t - 5 is negative because t5<0t - 5 < 0. Therefore, the speed (absolute value of velocity) is t5=5t|t - 5| = 5 - t.

    Distance=05(5t)dt\text{Distance} = \int_{0}^{5} (5 - t) \, dt

    05(5t)dt=[5tt22]05\int_{0}^{5} (5 - t) \, dt = \left[ 5t - \frac{t^2}{2} \right]_{0}^{5}

    =(5(5)522)(5(0)022)= \left( 5(5) - \frac{5^2}{2} \right) - \left( 5(0) - \frac{0^2}{2} \right)

    =(25252)0=2512.5=12.5= \left( 25 - \frac{25}{2} \right) - 0 = 25 - 12.5 = 12.5

  2. From t=5t = 5 to t=6t = 6: The velocity v(t)=t5v(t) = t - 5 is positive because t5>0t - 5 > 0. Therefore, the speed is t5=t5|t - 5| = t - 5.

    Distance=56(t5)dt\text{Distance} = \int_{5}^{6} (t - 5) \, dt

    56(t5)dt=[(t5)22]56\int_{5}^{6} (t - 5) \, dt = \left[ \frac{(t - 5)^2}{2} \right]_{5}^{6}

    =((65)22)((55)22)= \left( \frac{(6 - 5)^2}{2} \right) - \left( \frac{(5 - 5)^2}{2} \right)

    =(122)0=12=0.5= \left( \frac{1^2}{2} \right) - 0 = \frac{1}{2} = 0.5

Finally, adding these two distances gives the total distance traveled:

12.5+0.5=1312.5 + 0.5 = 13

Therefore, the total distance the object travels between t=0t = 0 and t=6t = 6 is 13 units, so the correct answer is B.

Would you like more details on any specific part of this solution? Here are five related questions to consider:

  1. How would the distance calculation change if the velocity function were different, such as v=t25v = t^2 - 5?
  2. Can you explain how to determine when an object changes direction given a different velocity function?
  3. What is the significance of integrating the absolute value of the velocity function in distance calculations?
  4. How can we use the concept of definite integrals to find the displacement instead of the total distance?
  5. What would the total distance be if the velocity function were v=t2v = t - 2 over the same interval?

Tip: When dealing with integrals of absolute value functions, always find where the function changes sign to properly split the integral.

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Math Problem Analysis

Mathematical Concepts

Calculus
Velocity and Distance
Definite Integrals

Formulas

Distance = ∫ |v(t)| dt
v(t) = t - 5

Theorems

Fundamental Theorem of Calculus
Absolute Value Integration

Suitable Grade Level

High School - Calculus