A body travels uniformly a distance of `( 13.8 +- 0.2) m` in a time `(4.0 +- 0.3) s`. Find the velocity of the body within error limits and the percentage error.

Options

A. `(3.5 +- 0.6 )ms^(-1)`
B. `(3.5 +- 0.3)ms^(-1)`
C. `(6.1 +- 0.6 )ms^(-1)`
D. `(6.1 +- 0.3 )ms^(-1)`

Answer

b

Explanation

Here `s = (13.8 +- 0.2)m`
`T = (4.0 +- 0.3)s`
`:. "Velocity" v = (s)/(t) = (13.8)/(4.0) = 3.45 ms^(-1)`
(Rounded off to first place of decimal
`:. (Delta v)/(v)= (Delta s)/(s)+(Delta t)/(t)= (0.2)/(13.8) + (0.3)/(4.0)`
`= (0.8+4.14)/(13.8 xx 4.0) = (4.94)/(13.8 xx4.0) = 0.0895`
or `Delta v = v xx 0.0895 = 3.45 xx 0.0895 = 0.3087`
`:. "velocity" = (3.5 +- 0.3)ms^(-1)`