Please help me on this problem?

Question

you place a watermelon on a spring scale at the supermarket. If the mass of the watermelons is 4.0 kg what is the reading on the scale?

Answer 1

It shows the mass in Newton, so, for 4 Kg it would show around 0.4 Newtons

(more precisely: 4/9.8) which is a bit higher than 0.4

Answer 2

If its mass is show  in Newton,it should be around 39.2 N

Answer 3

mass and weight are slightly different

mass = 4kg

Force = Mass x Acceleration

weight = 4 x 9.81(gravity) = 39.24 N

the scale might probably have a unit of KG on lbs there.