Strength of Materials Questions and Answers – Center of Gravity

This set of Strength of Materials Multiple Choice Questions & Answers (MCQs) focuses on “Center of Gravity”.

1. The point through which the whole weight of the body acts is called _____________
a) Inertial point
b) Center of gravity
c) Centroid
d) Central point
View Answer

Answer: b
Explanation: The centre of gravity of a body is the point through which the whole weight of the body acts. A body’s center of gravity is the point around which the resultant torque due to gravity forces vanishes. Where a gravity field can be considered to be uniform and the centre of gravity will be the same.

2. The point at which the total area of a plane figure is asssumed to be concentrated is called ____________
a) Centroid
b) Centre of gravity
c) Central point
d) Inertial point
View Answer

Answer: a
Explanation: The centroid is the point at which the total area of a plane figure is assumed to be concentrated. The centroid and centre of gravity are at the same point.

3. Where will be the centre of gravity of a uniform rod lies?
a) At its end
b) At its middle point
c) At its centre of its cross sectional area
d) Depends upon its material
View Answer

Answer: b
Explanation: The centre of gravity of a uniform rod lies at its middle point. The whole weight of the rod acts through its middle point.
advertisement
advertisement

4. Where the center of gravity of a circle lies?
a) At its centre
b) Anywhere on its radius
c) Anywhere on its circumference
d) Anywhere on its diameter
View Answer

Answer: a
Explanation: The whole weight of a circle can be assumed to act through its center. So the center of gravity of a circle is at its center.

5. Where will be the center of gravity of the following section will lie In coordinates?
Find the center of gravity of the following section if it lie In coordinates
a) (6,3)
b) (6,6)
c) (6,1.5)
d) (1.5,3)
View Answer

Answer: c
Explanation: The centre of gravity of this rectangular area will be half of 3cm from x-axis and half of 12 from the y-axis. therefore the center of gravity will be at (6,1.5).
Note: Join free Sanfoundry classes at Telegram or Youtube

6. Where will be the centre of gravity of the T section shown in the figure?
The centre of gravity of the T section shown in the figure is At 8.545cm
a) At 8.545cm
b) At 6.5cm
c) At 5cm
d) At 9.25cm
View Answer

Answer: a
Explanation: The center of gravity is given by, y = (a1y1 + a2y2) / (a1 + a2) = ( 36×11.5 + 30×5) / (36+30) = 8.545cm.

7. Where will be the center of gravity of the L-section shown in the figure?
The center of gravity of the L-section shown in the figure is (1.28,2.64)
a) (1.28,2.64)
b) (1.45,3.24)
c) (1.64,3.28)
d) (2.24,3.68)
View Answer

Answer: a
Explanation: The center of gravity is given by, y = (a1y1 + a2y2) / (a1 + a2) = (10×3.5 + 4×0.5) / (10+4) = 2.64cm.
This will on for the y-axis.
For the x-axis, The center of gravity is given by, x = (a1x1 + a2x2) / (a1 + a2) = (0x1 + 4×2) / (10+4) = 1.28cm.
So the center of gravity will be at (2.33, 4.33).
advertisement

8. Where will be the center of gravity of the figure shown ?
The center of gravity of the figure shown is (3.59,7.42)
a) (3.45,4.52)
b) (3.59,7.42)
c) (3.66,8.84)
d) (3.88,8.88)
View Answer

Answer: b
Explanation: Area of triangle = 50, area of rectangle = 100
The center of gravity is given by, y = (a1y1 + a2y2) / (a1 + a2) = (50×20/3 + 100×10) / (50+100) = 8.88cm.
This will on for the y-axis.
For the x-axis, The center of gravity is given by, x = (a1x1 + a2x2) / (a1 + a2) = (50×6.66 + 100×2.5) / (50+100) = 3.88cm.
So the center of gravity will be at (2.33, 4.33).

9. Where will be the center of gravity of an I section will be if the dimension of upper web is 2x10cm, lower web is 2×20 and that of flange is 2x15cm If the y-axis will pass through the center of the section?
a) 7.611cm
b) 9.51cm
c) 9.31cm
d) 11.5cm
View Answer

Answer: b
Explanation: The center of gravity is given by, y = (a1y1 + a2y2 + a3y3) / (a1 + a2 + a3) = (20×18 + 30×9.5 + 40×1 / (20 +30+40) = 1.611cm.
advertisement

Sanfoundry Global Education & Learning Series – Strength of Materials.

To practice all areas of Strength of Materials, here is complete set of 1000+ Multiple Choice Questions and Answers.

advertisement
advertisement
Subscribe to our Newsletters (Subject-wise). Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

Youtube | Telegram | LinkedIn | Instagram | Facebook | Twitter | Pinterest
Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

Subscribe to his free Masterclasses at Youtube & discussions at Telegram SanfoundryClasses.