Question

A 0.66-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 unstrained length increases by a factor of 7. What is the mass of the second block?

Answer 1

Answer:

So the mass of second block will be 3.96 kg

Explanation:

We have given mass of the block m = 0.66 kg

The spring is stanched by the factor 7

From hook's law we know that mg = kx

So $k=\frac{mg}{x}$

Let the mass of second block is M

So $(M+m)g=k(7x)$

Putting the value of m = 0.66 and  $k=\frac{mg}{x}$

$(M+0.66)g=\frac{mg}{x}(7x)$

$(M+0.66)=7m$

$(M+0.66)=7\times 0.66=4.62$

$M=3.96kg$

So the mass of second block will be 3.96 kg