Question

a solid and hollow cylindrical shaft have the same mass per unit length, the latter having an external diameter twice the internal one . show that the torsional rigidities produced in them by equal twisting couples are 5:3.

Answer 1

Answer:

ANSWER

Give, Both shafts have equal size, means outer diameter of the shaft is same,

Hallow shaft

Inner diameter =d

i

Outer diameter =d

0

Ref. image 1

Solid shaft

Outer diameter =d

0

Ref. image 2

→ If the size is same, There is more material used in the solid shaft, hence solid shaft will be stronger,

Assertion - wrong

→ Torsional rigidity of solid shaft is more than the torsional rigidity of the hollow shaft

Hence more torque is required in the solid shaft to produce the same deformation.

Reason - wrong

Option - D

solution