M3.4 materials and springs

Question 1

define stress

Answer 1

force per unit cross sectional area

Question 2

define strain

Answer 2

deformation of an object due to stress

Question 3

define young modulus

Answer 3

a measure of tensile stiffness of a solid material

Question 4

define ultimate tensile strength

Answer 4

the maximum amount of stress a material can withstand before a fracture

Question 5

define elastic

Answer 5

A property of a material to return to its original shape when the force is removed

Question 6

define plastic

Answer 6

A property of a material that doesnt return to its original shape when the force is removed

Question 7

define compressive forces

Answer 7

objeects being compressed or squished

Question 8

define tensile forces

Answer 8

applied when an object is stretched

Question 9

when springs are connected in series how is the spring constant

Answer 9

1/k1+1/k2 = 1/K
opposite to resistance in a circuit

Question 10

when connected in parallel how is spring constant found

Answer 10

k1+k2 =K

Question 11

insert straight line portion of force against extension graph
Explain why the work done on the cable when its extension changes from 3.0mm to 4.0mm
is greater than when its extension changes from 1.0mm to 2.0mm. [2]

Answer 11

greater area under the graph/ greater AVERAGE force

work done = area under the graph /work done = AVERAGE force * distance

Question 12

when experimenting to find the youngs modulus of a thin wire how might you ensure that results are reliable

part of a 6 marker

Answer 12

Measure diameter at 3 points and calculate a mean

use a long wire so that extension is measurable

measure extension as you take the load off to ensure you haven’t met the elastic limit of the material

before measure original length put an initial load on to ensure the wire is taut