Two people carry a heavy object by placing it on a board that is 2.2 meters long. One person lifts with a force of 750 N at one end while the other lifts the opposite end with a force of 360 N. Where is the object’s center of mass located along the board?

This means that the center of mass is locates 0.72m from the 750N force

Explanation:

Since the board is 2.2m long, that will be the length of the board.

Let the center of mass of the body be hinged at the center using a knife edge as shown in the diagram attached.

Let x be the distance from the 750N force to the knife edge and the distance from the 360N force to the knife edge be 2.2-x

Using the principle of moment which states that the sum of clockwise moment is equal to the sum of anti clockwise moment.

Moment = force × perpendicular distance

For ACW moment;

Moment = 750×x = 750x

For the CW moment;

Moment = 360 × (2.2-x)

Moment = 792-360x

Equating ACW moment to the clockwise moment we have;

750x = 792-360x

750x+360x = 792

1110x = 792

x = 792/1110

x = 0.72m

This means that the center of mass is locates 0.72m from the 750N force

the independent variable, or the one that is intentionally manipulated is the speed.