stress and strain

Question 1

what is stress

Answer 1

force applied per unit cross sectional area

Question 2

what is the equation for stress

Answer 2

F/A (force / cross sectional area)

Question 3

what is strain

Answer 3

relative deformation or change in shape that occurs in a material in response to an external force or load

Question 4

what is the equation for strain

Answer 4

ΔL/L (change in length / length)

Question 5

what is the area under the graph

Answer 5

work done (force x extension)

Question 6

what is young modulus

Answer 6

mechanical property of solid materials that measures the tensile or compressive stiffness when the force is applied lengthwise

Question 7

what are the significant points on a stress strain graph in order (5 points)

Answer 7

-proportional limit
-elastic limit
-yield point
-ultimate strength
-rupture strength or breaking point

Question 8

what is the proportional limit

Answer 8

the proportional limit determines the greatest stress that is directly proportional to strain

Question 9

what is the elastic limit

Answer 9

is the maximum stress or force per unit area within a solid material can change before being permanently deformed

Question 10

what does the gradient show on a stress and strain graph

Answer 10

the stiffness

Question 11

how to calculate the equation for young modulus

Answer 11

combine stress and strain ΔL/L and A/L

Question 12

what is the equation for young modulus

Answer 12

E = fL/AΔL = force x length / cross sectional area x change in length

Question 13

what is hookes law

Answer 13

F=KΔx where F = force, K is the constant of the spring, and x is the extension

Question 14

what does an elastic object show on a stress, strain graph

Answer 14

a large area under the graph

Question 15

what does a stiff object show on a stress, strain graph

Answer 15

very steep gradient over a small distance (area)

Question 16

what is an objects permanent set

Answer 16

the form an elastic objects will always return to

Question 17

what does a weak object show on a stress strain graph

Answer 17

small, low line doesn’t have a high stress value

Question 18

why might the gradient change due to the thickness of the material

Answer 18

-the steepness would vary
-because less or more force is required

Question 19

what does the area under a force-extension graph show

Answer 19

the work done it is half the graph due to the equation = 1/2 (force x extension)