The displacement covered by a body in time `(5.0 +- 0.6) s is ( 40.4 +- 0.4 ) m`. Calculate the speed of the body . Also determine the percentage error in the speed.

Explanation

Here ` s = 40.0 +- 0.4 m and t = 5.0 +- 0.6 s`. Therefore, speed ,
`v = ( s) /( t) = ( 40.0)/(5.0) = 8.0 m s^(-1)`
As ` v = (s)/( t) , therefore , ( Delta v)/( v) = ( Delta s)/( s) + ( Delta t)/(t)`
Here `Delta s = 0.4 m , s = 40.0 m , Delta t = 0.6 s, t = 5.0 s`. Therefore,
or `( Delta v)/( v) = ( 0.4)/( 40.0) + ( 0.6) / (5.0) rArr Delta v = [ 0.01 + 0.12 ] xx 8.0 = 1.04`
Hence , `v = ( 8.0 +- 1.04) ms^(-1)`, percentage error
`(( Delta v)/( v) xx 100) = 0.13 xx 100 = 13%`