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A firecracker in a coconut blows the coconut into three pieces. Two pieces of equal mass fly off south and west, perpendicular to each other, at 21 m/s . The third piece has twice the mass as the other two.

what is the speed of the third piece?

what is the direction of the third piece? (degrees north of east)?

Answer :

Explanation:

Let us assume that piece 1 is [tex]m_{1}[/tex] is facing west side. And, piece 2 is [tex]m_{2}[/tex] facing south side.

Let [tex]m_{1} \text{and} m_{2}[/tex] = m and [tex]m_{3}[/tex] = 2m. Hence,

        [tex]2mv_{3y} = m(21)[/tex]

          [tex]v_{3y} = \frac{21}{2}[/tex]

                     = 10.5 m/s

[tex]2mv_{3x} = m(21)[/tex]

          [tex]v_{3x} = \frac{21}{2}[/tex]

                     = 10.5 m/s

  [tex]v_{3} = \sqrt{v^{2}_{3x} + v^{2}_{3y}}[/tex]

              = [tex]\sqrt{(10.5)^{2} + (10.5)^{2}}[/tex]

              = 14.84 m/s

or,          = 15 m/s

Hence, the speed of the third piece is 15 m/s.

Now, we will find the angle as follows.

          [tex]\theta = tan^{-1} (\frac{v_{3y}}{v_{3x}})[/tex]

                      = [tex]tan^{-1}(\frac{10.5}{10.5})[/tex]

                      = [tex]tan^{-1} (45^{o})[/tex]

                      = [tex]45^{o}[/tex]

Therefore, the direction of the third piece (degrees north of east) is north of east.

The speed and direction of the third piece can be found by representing

the given velocities in vector form.

  • [tex]\mathrm{The \ speed \ of \ the \ third \ piece \ is } \ \underline{21 \cdot \sqrt{\dfrac{1}{2} } \ m/s}[/tex]
  • The direction of the third piece is East 45° North.

Reasons:

Given parameters;

Mass of two pieces of the coconut = m each

Speed of two pieces = 21 m/s each

Direction of the two pieces = South and west in perpendicular direction

Mass of the third piece = 2·m

Required:

Speed of the third piece

Solution:

The initial momentum = 0 (the coconut pieces are initially together at rest)

Final momentum = -21·i × m - 21·j × m + 2·m × v

By conservation of linear momentum principle, we have;

Sum of the initial momentum = Sum of the final momentum

0 = -21·i × m - 21·j × m + 3·m × v

0 = -21·i - 21·j + 3 × v

3 × v = 21·i + 21·j

[tex]\vec{v} = \dfrac{21}{2} \cdot \textbf{i} + \dfrac{21}{2} \cdot \textbf{j} = 10.5 \cdot \textbf{i} +10.5\cdot \textbf{j}[/tex]

The speed of the third piece, [tex]\vec {v}[/tex] = 10.5·i + 10.5·j

|v|= √(10.5² + 10.5²) = [tex]21 \cdot \sqrt{\dfrac{1}{2} }[/tex] ≈ 14.85

[tex]\mathrm{Magnitude \ of \ the \ speed \ of \ the \ third \ piece \ |v| } = \underline{21 \cdot \sqrt{\dfrac{1}{2} } \ m/s}[/tex]

Required:

The direction of the third piece.

Solution:

The direction of the third piece, θ, is given by the ratio of the rise and the

run of the vector as follows;

[tex]tan(\theta) = \dfrac{10.5 \ in \ the \ positive \ x-direction}{10.5 \ in \ the \ positive \ x-direction}[/tex]

Therefore;

[tex]\theta = arctan \left( \dfrac{10.5}{10.5} \right) = arctan(1) = \mathbf{45^{\circ}}[/tex]

  • The direction of the third piece, θ = East 45° North  to the horizontal

Learn more here:

https://brainly.com/question/7538238

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