A spring that is 0.7 m in length elongates to 1.06 m when a 20 Newton force is exerted to stretch the spring. By how much more does the spring stretch when an additional 8 Newtons of force is exerted on it?

1.01
0.053
0.072
0.45
0.144
0.561
0.736
1.06

I think there are 3 parts to figuring this out:

#1) 20 N + 8 N + 28N
#2) idk...
#3) idk...

Please help!

3 answers

Extens
Extension caused by first force = 1.06-0.7=0.36cm......since F ~ e...... F= ke...... F/e = k (constant of proportionality).... F1/F2 =e1 /e2...... F2=20+8=28N......F1=20N......e1=0.36cm......e2=?....... F1/F2 =e1 /e2...... 20/28=0.36/e2.....e2=0.504......
A spiral spring is stretched 0.6cm by a force of 20N find the original Leng of the material if a force of 40N stretches a material of 30cm