A block of gelatine is 60 mm be 60 mm be 20 mm when unstressed. A force of 0.245 N is applied tangentially to the upper surface, causing a 5 mm displacement relative to the lower surface. Following observations are made regarding the block. (i) the shearing strees develop on surface is 68.1 Pa
(ii) the shearing strain develop on surface is 0.25 Pa
(iii) the shear modulus of material is `272(N)/(m^2)`
Regarding above statements we can say:

Options

A. only statements (i) and (iii) are correct
B. only statements (ii) and (iii) are correct
C. only statements (i) and (ii) are correct
D. all the statements are correct

Answer

D

Explanation

(i) Stress`=(F)/(A)=(0.245)/(36xx10^-4)=68.1Pa`
(ii) Strain`=theta=(r )/(h)=(5)/(20)=0.25`
(iii) Shear modulus`=S`
`((F)/(A))/(tantheta)=(68.4)/(0.25)=272.4(N)/(m^2)`