Determination of Young modulus of a material by a simple method

Question 1

why is thin and long copper wire used

Answer 1

maximise extension

reduce uncertainty

Question 2

how is measurement tricky

Answer 2

extension is still small

Question 3

how is the accuracy of the measurement increased

Answer 3

• using a vernier or micrometer

Question 4

How is the equipment set up

Answer 4

• wire clamped at one end
• marker attached to wire
• mm rule scale
• pulley
• load attached to end

Question 5

what is the proceudre

Answer 5

• tightly clamped wire to prevent slipping
  
  • long as possible
• weights added until the wire is just taught
  
  • initial reading of the marker is taken
• extension determined for additional loads

Question 6

precaution

Answer 6

• place crash pad under the weights to prevent them hitting the floor directly when the wire breaks
• do not put feet under the weights
• wear goggles for protection when the wire breaks

Question 7

how is cross sectional area determined

Answer 7

• use a micrometer to measure the diameter of the wire in several places
• take an average
  
  • assume circle

Question 8

how is YM calculated

Answer 8

plot graph of stress over strain

gradient is YM