Question

Define the center of the gravity of a rigid object. How is it related to the center of mass?

What evidence supports the idea that the weight of an extended object acts at the center of gravity?

Find the perpendicular distance between the axis of rotation and the lines of action of W and the 100 gm mass.

Explain the principle of the triple-beam balance.

Figure 5, m1=400 grams, m2=200, m3=100 grams would there be a problem balancing the meter stick? How could you remedy the situation.

A uniform meter stick is at rotational equilibrium when a mass is 200 grams is suspended at the 5cm mark, a mass of 150g is suspended at the 80 cm mark, and the support is placed at the 40 cm mark. What is the mass of the meter stick?

Answer 1

1) Center of gravity of a rigid object is defined as a point in a body around which the resultant torque due to gravity forces vanish which means that for any rigid body, the two points are the same, because you can model rigid bodies in free fall as if gravity acted only on the center of mass, and forces.

2) The center of gravity is the point where gravity appears to act. Whereas the center of mass is the mean position of the mass in an object. For many objects, these two points are in exactly the same place. But they are only the same when the gravitational field is uniform across an object.