Question

A spring stretches 0.2 cm per newton of applied force. An object is suspended from the spring and a deflection of 3 cm is observed. If g = 9.81 m/s?, what is the mass of the object, in kg?

Answer 1

Answer:

$m=1.53kg$    

Explanation:

To solve this problem we use the Hooke's Law:

$F=k*\Delta x$     (1)

F is the Force needed to expand or compress the spring by a distance Δx.

The spring stretches 0.2cm per Newton, in other words:

1N=k*0.2cm ⇒ k=1N/0.2cm=5N/cm  

The force applied is due to the weight

$F=mg$

We replace in (1):

$mg=k*\Delta x$  

We solve the equation for m:

$m=k*\Delta x/g=5*3/9.81=1.53kg$