Instructor's Notes and Solutions:
Center of Gravity

Materials needed:

1 m heavy thread
1 large paper clip
1 small paper clip
scissors
one half of a manila folder
pencil
meter stick

Solutions to Questions:

1.) Yes, if the system includes two or more objects, or an irregular shape.

2.) The center of gravity for:

a.) a CD is in the center.
b.) a horseshoe is as such:

c.) two identical chocolate candies placed 1 cm apart is as such:

 
 

3.) The center of gravity for a meterstick is at the middle of its length. Balance it on your finger and the pivot point where the ruler lies horizontal is the center of gravity.

4.) For each part:

a.) Diagram:

b.) Solution: Calculate the weight for each mass. 

weight = mass x 9.8m/s2

 
mplane = 2000kg mpilot = 70kg
W = 19.6x104 N W = 686 N
rcmplane = 3.0m rpilot = 1.0m
mcargo = 400kg
W = 3920 N
rcargo = 2.0m
How far from the front of the plane is the Center of Gravity?

= 2.81m from the nose of the plane.

Note to instructor: You may factor out (9.8 m/s2) from the numerator and denominator to simplify the calculations, or use it to emphasize weight as a force.

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