1. A spring has a natural length of 10 in. An 800-lb force stretches the spring to 14 in.
(a) Find the force constant.
(b) How much work is done in stretching the spring from 10 in. to 12 in.?
(c) How far beyond its natural length will a 1600-lb force stretch the spring

Question

1. A spring has a natural length of 10 in. An 800-lb force stretches the spring to 14 in.
(a) Find the force constant.
(b) How much work is done in stretching the spring from 10 in. to 12 in.?
(c) How far beyond its natural length will a 1600-lb force stretch the spring

unklerhaukus · Answer

Hooks Law for a spring$$F=-kx$$

unklerhaukus · Answer

but first i would make all the units SI
4 in = 0.1016 m
800 lb = 4.448 N

unklerhaukus · Answer

so 
$$k={4.448 N \over 0.1016m}$$
and a newton N=kg.m.s^-2
so
$$k=43.78 ~kg.s^{-2}$$