In a force diagram, what does the length of an arrow represent?

• A. The speed of the object
• B. The strength of the forces acting on an object
• C. The direction of motion
• D. The mass of the object

Answer: (B)

In force diagrams, arrows represent forces, and how long each arrow is shows how strong that force is. The length is tied to the magnitude of the force—longer arrows mean bigger forces, shorter arrows mean smaller ones. The direction of each arrow shows the direction the force acts, while the motion or speed of the object isn’t read from these lengths. This is why the correct idea is that the length reflects the strength of the forces acting on the object. For example, a heavier pull from gravity would be shown with a longer downward arrow than a smaller push from friction, and the net effect on motion comes from combining those forces, not from how fast the object is moving.