# If the length of a #63 cm# spring increases to #98 cm# when a #15 kg# weight is hanging from it, what is the spring's constant?

##### 1 Answer

May 14, 2018

#### Explanation:

We use Hooke's law, which states that,

where:

#F# is the force exerted on the spring in newtons

#k# is the spring constant, usually in newtons per meter

#x# is the extension of the spring in meters

Here:

#F=15 \ "kg"*9.8 \ "m/s"^2=147 \ "N"#

#x=(98 \ "cm"-63 \ "cm")*(1 \ "m")/(100 \ "cm")=0.35 \ "m"#