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A bird moves from point (1, -2, 3) to (4...

A bird moves from point `(1, -2, 3)` to `(4, 2, 3)`. If the speed of the bird id `10 m//s`, then the velocity of the bird is :-

A

`5 (hati-2hatj+3hatk)`

B

`5 (4hati+2hatj+3hatk)`

C

`0.6 hat(i)+0.8 hat(j)`

D

`6hat(i)+8hat(j)`

Text Solution

Verified by Experts

The correct Answer is:
D
`vec(v)=((4-1)hat(i)+(2+2)hat(j)+(3-3)hat(k))/sqrt(3^(2)+4^(2)+0^(2))=(3hati+4hatj)/5`
`vec(v)=|vec(v)|hat(v)=10((3hat(i)+4hatj)/5)=6hat(i)+8hat(j)`
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Knowledge Check

  • The angle of elevation of a bird sitting on top of a tree as seen from the point at a distance of 20m from the base of the tree is 60^(@) . Then, the height of the tree is ……..m

    A
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    A
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    C
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