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3. Which of the following equations are dimensionally correct?
(a)`v_f = v_i + ax`
(b)`y=(2m)cos(kx)`,where `k=2m^-1`
match SI unit
(b) only
SI unit of `v` is `m//s`
SI unit of `x` and `y` a `m`
SI unit of `a` is `m//s^2`
(a)
`m//s = m//s + m//s^(2)`
`m//s = m//s + m^2//s^2` which cannot match.
(b)
`m = (2m)(cos(2m^(-1)times(m))`
`=>m = m cos(2)`
`=> m = m`
which is dimensionally correct.
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