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A particle moves in XY plane such that i...

A particle moves in XY plane such that its position, velocity and acceleration are given by
`vec(r)=xhat(i)+yhat(j), " "vec(v)=v_(x)hat(i)+v_(y)hat(j), " "vec(a)=a_(x)hat(i)+a_(y)hat(j)`
Which of the following condition is correct if the particle is speeding down?

A

`xv_(x)+yv_(y) lt 0`

B

`xv_(x)+yv_(y) gt 0`

C

`a_(x)v_(x)+a_(y)v_(y) lt 0`

D

`a_(x)v_(x)+a_(y)v_(y) gt 0`

Text Solution

Verified by Experts

The correct Answer is:
C
For speeding down `vec(a).vec(v) lt 0 rArr a_(x)v_(x)+a_(y)v_(y) lt 0`
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