A particle starts from rest at the point [tex]\(A(1,-2,-3) \text{ m}\)[/tex] and reaches the point [tex]\(B(3,4,5) \text{ m}\)[/tex]. The magnitude of displacement of the particle is:

A. [tex]\(7.1 \text{ m}\)[/tex]
B. [tex]\(3.7 \text{ m}\)[/tex]
C. [tex]\(3.4 \text{ m}\)[/tex]
D. [tex]\(8.5 \text{ m}\)[/tex]



Answer :

To determine the magnitude of the displacement of the particle moving from point [tex]\( A(1, -2, -3) \)[/tex] to point [tex]\( B(3, 4, 5) \)[/tex], we perform the following steps:

1. Calculate the components of the displacement vector [tex]\(\vec{d}\)[/tex]:
- The displacement vector [tex]\(\vec{d}\)[/tex] has components given by the differences between the coordinates of point B and point A.
- Determine the differences along the x, y, and z axes:
[tex]\[ d_x = x_B - x_A = 3 - 1 = 2 \][/tex]
[tex]\[ d_y = y_B - y_A = 4 - (-2) = 4 + 2 = 6 \][/tex]
[tex]\[ d_z = z_B - z_A = 5 - (-3) = 5 + 3 = 8 \][/tex]

2. Determine the magnitude of the displacement vector [tex]\(\| \vec{d} \|\)[/tex]:
- The magnitude of the displacement vector [tex]\(\| \vec{d} \|\)[/tex] is given by the Euclidean distance formula for three-dimensional space:
[tex]\[ \| \vec{d} \| = \sqrt{d_x^2 + d_y^2 + d_z^2} \][/tex]
- Plugging in the calculated components:
[tex]\[ \| \vec{d} \| = \sqrt{2^2 + 6^2 + 8^2} \][/tex]
- Calculate each term inside the square root:
[tex]\[ 2^2 = 4, \quad 6^2 = 36, \quad 8^2 = 64 \][/tex]
- Sum these squares:
[tex]\[ 4 + 36 + 64 = 104 \][/tex]
- Thus,
[tex]\[ \| \vec{d} \| = \sqrt{104} \][/tex]
- Calculating the square root:
[tex]\[ \sqrt{104} \approx 10.198 \][/tex]

Therefore, the magnitude of the displacement of the particle is approximately [tex]\(10.198 \, m\)[/tex].

Thus, the correct answer is none of the options provided [tex]\((a) 7.1 \, m, (b) 3.7 \, m, (c) 3.4 \, m, (d) 8.5 \, m\)[/tex]. If there had been an option for [tex]\(10.2 \, m\)[/tex], it would have been a closer match.