Got a couple of simple Hooke's Law questions in a text book I'm using, but I cannot get the answers given in the book.
Question 1: What force is required to stretch a spring with spring constant 0.2 N/cm a distance of 5 cm?
Question 2: A vertical spring stretches 5 cm under a load of 100 g. Determine the spring constant.
The formula for Hooke's Law is F= kx (K = constant and x = extension)
So for Q1 I simply multiply 0.2 N/cm with 5 cm and get a force of 1 Newton.
But the book says it's 0.01 N. ??
For Q2 I work out the force of the 100g mass: (0.1 Kg x 10 N/Kg for gravity = 1 Newton)
Then I divide Force by Extension which is 1 N / 5 cm = 0.2 N/cm
But book says it's 0.05 N/cm ??
What am I doing wrong please?
Stick or dump?