Răspuns:
Fe = 100 N
Δl = l2-l1 = 20-15 = 5 cm = 0,05 m
k = Fe / Δl = 100 N / 0,05 m = 2000 N/m
m = 12 kg
G = m × g = 12 kg × 10N/kg = 120 N
In cazul asta , Fe = G = 120 N
Am aflat constanta elastica , k = 2000 N/m
deci Δl = Fe / k = 120 N / (2000 N/m) = 0,06 m = 6 cm.