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Need help in this vector math question….?

Update:

A ship is moving with a constant speed of 10(√ 5 ) km/h parallel to the vector i + 2j and is initially at the origin.

Let the velocity of the ship be V

The solution:

V= 10(√ 5)[ (√ 5)^( -½)] (i + 2j )

Why is the solution so?

4 Answers

Relevance
  • 1 decade ago
    Favorite Answer

    Velocity, as u know, is a vector. Thus it has magnitude and direction. Both have been given in the question. A vector, given its magnitude and direction, can be derived by multiplying its mag. and dir. The direction, however, should be the unit vector in the given direction. Else, we will make a mistake by including the magnitude of 1+2j. The unit vector is derived by dividing the given vector by its magnitude. Thus,

    the asnwer should be V= magnitude * unit vector in the direction of 1+2j.

    which is the given answer

  • 1 decade ago

    Constant speed = 10 (5)^1/2

    Direction vector = (i+2j)/(1+4)^1/2

    = 1/(5)^1/2. (i+2j)

    velocity = 10 (5)^1/2. 1/(5)^1/2. (i+2j)

    = 10 (i+2j)

  • 1 decade ago

    I believe this is a typo.

    The correct answer should be V= 10(√ 5) (i + 2j )

  • 1 decade ago

    what question?

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