The percentage errors in the measurement of mass and speed are 2% and 4%respectively. Then find maximum error in the measurement of K.E?

Answer 1

KE = (1/2) m v^2

dKE= (v^2/2)dm + mvdv

dm = .02 m
dv = .04 v

dKE = (v^2/2) .02 m + m v .04 v
= m v^2/2 (.02) + mv^2/2 (.08 )
= 0.10 KE

= 10%

because velocity is squared, it alone counts for 2*4 = 8%