Mechanics - Elastic Strings and Springs Flashcards
What are elastic collisions about?
Which law?
Hooks law?
What is a very common mistake?
Strings and springs are very different with only 1 letter difference
What are the difference between strings and springs?
Strings can’t be compressed
Springs can be (compressed and therefore push back)
What is Hooks law?
Tension is proportional to extention
What does Hook’s Law imply (equation)
λ - modulus of elasticity
What does λ,x and l stand for?
λ - modulus of elasticity
l - the natural length
x - extension of the string
What is λ measured in?
Newtons
What is l measured in?
Meters
What actually is the modulus of elasticity (λ)?
The force needed to double its length (stiffness)
What is a good way to differentiate between strings and springs after reading the question?
Draw them differently
What is the general method for the first 2 sub topics in this chapter?
Split forces so that you can compare the force (from the weight from a object attacked to the rope) to the forces going up (mainly tension in the string=Weight)
Using F=ma when acceleration is involved
What is the equation for elastic potential energy stored?
When does EPE occur?
When a spring or string is being extended (or compressed) which takes work to be done
What is the logic behind the EPE equation?
The work done changes as the spring is compressed/extended so:
What is the work energy principle (equation) and how is it now different?
E2 = E1-Fs.s
Now each energy can have EPE as well
