# An object with a mass of 6 kg is hanging from a spring with a constant of 4 (kg)/s^2. If the spring is stretched by 18 m, what is the net force on the object?

Feb 22, 2017

The net force is $- 13.2 N$ (acting upwards)

#### Explanation:

We resolve in the vertical direction ${\downarrow}_{+}$

The weight acts downwards

${\vec{F}}_{1} = 6 g = 6 \cdot 9.8 = 58.8 N$

According to Hooke's Law

${\vec{F}}_{2} = - k x$

$= - 4 \cdot 18 = - 72 N$

The net force is

$\vec{F} = {\vec{F}}_{1} + {\vec{F}}_{2} = 58.8 - 72 = - 13.2 N$