True weight is the force of gravity pulling you downward. Apparent weight is the support force pushing up on you, like the force from a floor or scale. They are often the same, but they can be different when you are accelerating.

Audio Explanation

Prefer to listen? Here's a quick audio summary of weight and apparent weight.

Visual Representation

Comparison of Normal Force and Weight in different acceleration states A three-panel free-body diagram showing a box on a surface. In the first panel (no acceleration), the upward normal force arrow and downward weight arrow are equal in length. In the second panel (upward acceleration), the upward normal force arrow is longer than the weight arrow. In the third panel (downward acceleration), the upward normal force arrow is shorter than the weight arrow. No Acceleration Normal Force Weight Normal Force = Weight Upward Acceleration Acceleration Normal Force Weight Normal Force > Weight Downward Acceleration Acceleration Normal Force Weight Normal Force < Weight

What is True Weight?

Your true weight is the force of gravity acting on you.

  • Formula: $F_g = mg$

    • $F_g$ = weight in newtons (N)
    • $m$ = mass in kilograms (kg)
    • $g$ = gravitational field strength, about $9.8 \text{ m/s}^2$

Your true weight usually stays the same unless your mass changes or you move far from Earth.

What is Apparent Weight?

Your apparent weight is the normal force pushing up on you.

This is the force you feel when you stand on the ground, stand on a scale, or ride in an elevator.

  • A bathroom scale measures your apparent weight.
  • Apparent weight depends on acceleration.
  • Apparent weight can be greater than, less than, or equal to true weight.

How Apparent Weight Changes

There are two main forces acting on you in an elevator:

  • Weight ($F_g$): Pulls downward
  • Normal Force ($F_N$): Pushes upward

Newton’s Second Law gives:

\[F_N - F_g = ma\]

So:

\[F_N = F_g + ma\]
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