Question

1.

Given the angle of rotation is small and the materials remain linear elastic, which statement below is incorrect for the torsional behavior of a long straight circular shaft:

	a.	Straight member remains straight
	b.	Section-shape remains unchanged
	c.	End of member may warp
	d.	Plane section remains plane

2.

The unit for a shaft’s polar moment of inertia J is:

	a.	m2
	b.	m3
	c.	kPa
	d.	m4

3.

Provided that the bending formation of a straight member is small and within elastic range. Which of the following statements is incorrect? (select all that apply)

	a.	The length of the longitudinal axis remains unchanged
	b.	Cross-sections remains perpendicular to the longitudinal axis
	c.	Plane sections remain plane
	d.	In-plane distortion of cross-sections with respect to the longitudinal axis is negligible

4.

Which of the following statements is correct for bending of a straight member?

	a.	Bending stress is inversely proportional to the moment of inertia of the section
	b.	Bending stress does not depend on the moment of inertia of the section
	c.	Bending stress is proportional to the moment of inertia of the section
	d.	Bending stress is proportional to the square of the moment of inertia of the section

5.

Which of the following statements is true? The flexure formula for a straight member can be applied only when: (select all that apply)

	a.	the principal axes have their origin at the centroid
	b.	bending remains in the elastic region
	c.	bending occurs about axes that represent the principal axes of inertia for the section
	d.	the principal axes are orientated along an axis of symmetry, if there is one, and perpendicular to it

Answer 1

1)

c)End of member may warp

When the rotion apply the torsion going to happen but in torsion the shape and cross section not going to change as shown in the figure

2)

d) m⁴

as we know that the polar moment of interia for circular section is prpotional to d⁴ so unit is m⁴ .

3)

d)In-plane distortion of cross section is to the longitudinal axis not negligible

due to bending formation is very small length of longitudnal axis is same as previous

in any banding case cross section is always perpendicular to axis and shape of cross section is not chage

4)

a)Bending stress is inversely proportional to the moment of inertia of the section

As we know

so bending stress is inversely proportional to moment of interia

5)

All option are true

Flexure formula can be applicable when there is bending occur and member is straight so for all option it is applicable

Hope you got you answer for any doubt comment below and kindly rate my answer