Answer:
workdone =30.5J or 22.5 Ib.ft
Step-by-step explanation:
From Hookes law , F=ke
k=F/e
F=10 Ib , e= 2f
K=10/2ft =5 Ib/ft
when e = 5ft
F=ke
F= 5 Ib/ft *5 ft
F=25 Ib
force required for stretching from 2ft to ft beyond its natural length equals =25-10 =15 Ib
Workdone in stretching a spring is = 1/2Fe
= 1/2* 15 Ib * 3ft
=22.5 Ibft
1 Ibft is equal to 1.35582joules.
22.5 Ibft= 22.5*1.35582 = 30.5059J
workdone =30.5J
