Example: A Block On An Inclined Plane
A simple free body diagram, shown above, of a block on a ramp illustrates this.
- All external supports and structures have been replaced by the forces they generate. These include:
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- mg: the product of the mass of the block and the constant of gravitation acceleration: its weight.
- N: the normal force of the ramp.
- Ff: the friction force of the ramp.
- The force vectors show direction and point of application and are labeled with their magnitude.
- It contains a coordinate system that can be used when describing the vectors.
Some care is needed in interpreting the diagram. The line of action of the normal force has been shown to be at the midpoint of the base but its true location can only be found if sufficient further data is given. The diagram as it stands would need to be modified were we told that the block is in equilibrium.
There is a potential difficulty also with the arrow representing friction. The engineer who drew this diagram has used the tip of the arrow to indicate the point of application of a force. (See the other force arrows in the diagram). Now, the tip of the friction arrow is at the highest point of the base. The intention however is not to indicate that the friction acts at that point. The engineer in this instance has assumed a rigid body scenario and that the friction force is a sliding vector and thus the point of application is not relevant. The engineer has tried to indicate that the friction acts all along the whole base by drawing an arrow all along the base but such artistic ploys are a matter of personal choice.
Read more about this topic: Free Body Diagram
Famous quotes containing the words block, inclined and/or plane:
“Painting consumes labour not disproportionate to its effect; but a fellow will hack half a year at a block of marble to make something in stone that hardly resembles a man. The value of statuary is owing to its difficulty. You would not value the finest head cut upon a carrot.”
—Samuel Johnson (1709–1784)
“In any case, raw aggression is thought to be the peculiar province of men, as nurturing is the peculiar province of women.... The psychologist Erik Erikson discovered that, while little girls playing with blocks generally create pleasant interior spaces and attractive entrances, little boys are inclined to pile up the blocks as high as they can and then watch them fall down: “the contemplation of ruins,” Erikson observes, “is a masculine specialty.””
—Joyce Carol Oates (b. 1938)
“It was the most ungrateful and unjust act ever perpetrated by a republic upon a class of citizens who had worked and sacrificed and suffered as did the women of this nation in the struggle of the Civil War only to be rewarded at its close by such unspeakable degradation as to be reduced to the plane of subjects to enfranchised slaves.”
—Anna Howard Shaw (1847–1919)