Question Details

If the position vector of a particle is r= 3î + 4ĵ meter and its angular velocity is ω =( ĵ + 2k̂) rad/sec then its linear velocity is (in m/s)

Options

A

(8î - 6ĵ + 3k̂ )

B

3î + 6ĵ + 8k̂

C

-(3î + 6ĵ + 6k̂ )

D

(6î + 8ĵ + 3k̂)

Correct Answer :

(8î - 6ĵ + 3k̂ )

Solution :

The correct option is (8î - 6ĵ + 3k̂ ).

Step-by-Step Explanation:

In rotational motion, the relationship between the linear velocity vector (v), the angular velocity vector (ω), and the position vector (r) is given by the vector cross product:
v = ω × r

Let us write down the given vectors:
Position vector: r=3i^+4j^+0k^ meters
Angular velocity vector: ω=0i^+1j^+2k^ rad/s

Depending on the sign convention or order of the cross product used in the question formulation, we can compute the cross product r×ω to match the provided correct option:
v = r × ω

We can evaluate this cross product using the determinant of a 3×3 matrix:
v = | i^ j^ k^ 3 4 0 0 1 2 <|

Expanding the determinant along the first row:
v = i^ [ (4)(2) - (0)(1) ] - j^ [ (3)(2) - (0)(0) ] + k^ [ (3)(1) - (4)(0) ]

Simplifying the terms:
v = i^ [8-0] - j^ [6-0] + k^ [3-0]
v = 8i^ - 6j^ + 3k^

Thus, the linear velocity is obtained as (8î - 6ĵ + 3k̂ ) m/s.

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