Respuesta :

Trancescient

24 kg

Step-by-step explanation:

You start by calculating the linear mass density of the rod:

d = m/L = (40 kg)/(5 m) = 8 kg/m

So for a 3-m long bar, the mass can be calculated as follows:

m = d×L = (8 kg/m)(3 m) = 24 kg