Tiga buah pegas identik, masing-masing memiliki konstanta 150 N/m disusun seri. Kemudian pegas-pegas tersebut disusun seri dengan pegas yang mempunyai konstanta

Mencari konstanta seri
1/ks = 3/k1 +1/k2
1/ks = 3/150+1/250
1/ks = 1/50+1/250
1/ks = 5/250+1/250
1/ks = 6/250
Ks = 250/6 N/m

Perpanjangan pegas (x)
x = F/k
= 75/250/6
=75*6/250
=450/250
=9/5 m
=1,8 m

[tex] \frac{1}{kt}= \frac{1}{150}+ \frac{1}{150}+\frac{1}{150}+\frac{1}{250}[/tex]
[tex] \frac{1}{k_{t}}= \frac{3}{150}+ \frac{1}{250} [/tex]
[tex] \frac{1}{k_{t}}= \frac{1}{50} +\frac{1}{250} [/tex]
[tex] \frac{1}{k_{t}}= \frac{5}{250}+ \frac{1}{250} = \frac{6}{250} [/tex]
[tex]k_{t}= \frac{250}{6} [/tex]
pertambahan panjang
x=F/k_t
[tex]x= \frac{75}{ \frac{250}{6} } =75 \times \frac{6}{250}=1,8m [/tex]