Question

A thin 1m long rod has a radius of 5 mm. A force of 50knis applied at one end to determine its young's modulus. Assume that the force is exactly known.

Answer 1

you can use formulae load× Load arm = effort × effort arm

Answer 2

Question : A thin 1m long rod has a radius of 5 mm. A force of 50knis applied at one end to determine its young's modulus. Assume that the force is exactly known. If the least count in the measurement of all the lengths is 0.01 mm, which of the following statements is false?

A. The maximum value of Y that can be determined is $10^{14}$ N/$m^{2}$

B. $\frac{ΔY}{Y}$ gets minimum contribution from the uncertainty in length

C. $\frac{ΔY}{Y}$ gets maximum contribution from the uncertainty in strain

D. The figure of merit is the largest for the length of the rod

Answer : A. is false

Y = $\frac{Fl}{πr^{2}Δl}$

Y = 50 pi * 10^3 * 1 / [pi * (0.005)^2 * 0.01 * 10^-3]

= 2 x $10^{14}$ N/m2