A 0.47-kg block is hung from and stretches a spring that is attached to the ceiling. A second block is attached to the first one, and the amount that the spring stretches from its unstretched length triples. What is the mass of the second block

The mass of the second block is 0.94 kg

Explanation:

Given;

mass of the first block, m₁ = 0.47 kg

let the mass of the first block and second block = m₂

According to Hook's law;

F = kx

where;

F is the applied load (force)

k is the elastic constant

x is the extension of the elastic material

According to Newton's law of motion;

F = ma = mg

Thus,

mg = kx

mass of the second block alone = 1.41 - 0.47 = 0.94 kg

Therefore, the mass of the second block is 0.94 kg

learn it on the intertant so you can solve

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.