Question

How much will a 60 m steel tape 1 cm wide and 0.05 cm thick stretch under a pull of a
force of 300 N if Young’s modulus of steel is 2 × 10^11 N/m2.

Answer 1

Explanation:

d=0.5mm,Y=2×1011,l=1m

       △l=AyFl=4πd2ymgl=4π×(5×10−4)2×2×10111.2×10×1

△l=43.2×25×10−8×2×10111.2×10×1

 = 0.8×25×2×10312=40×10312=0.3mm

So 3rd division of vernier scale will coincide with main scale.

Answer 2

Answer:

d=0.5mm,Y=2×1011,l=1m

      △l=AyFl=4πd2ymgl=4π×(5×10−4)2×2×10111.2×10×1

△l=43.2×25×10−8×2×10111.2×10×1

= 0.8×25×2×10312=40×10312=0.3mm

So 3rd division of vernier scale will coincide with main scale.