Normal Force Physics Example 4

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Example 4

hard
A person (60 kg60 \text{ kg}) stands in an elevator accelerating upward at 2 m/s22 \text{ m/s}^2. What normal force does the floor exert on the person? Use g=9.8 m/s2g = 9.8 \text{ m/s}^2.

Solution

  1. 1
    Apply Newton's second law in the vertical direction: N−mg=maN - mg = ma (upward acceleration).
  2. 2
    N=m(g+a)=60(9.8+2)=60×11.8=708 NN = m(g + a) = 60(9.8 + 2) = 60 \times 11.8 = 708 \text{ N}
  3. 3
    This is greater than the person's weight of 588 N588 \text{ N}, which is why you feel heavier in an accelerating elevator.

Answer

N=708 NN = 708 \text{ N}
In an accelerating elevator, the normal force differs from the weight. Upward acceleration increases the normal force (apparent weight), while downward acceleration decreases it.

About Normal Force

The perpendicular contact force that a surface exerts on an object pressing against it, directed away from the surface.

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More Normal Force Examples

Example 1 easy

A [formula] box rests on a horizontal floor. What is the normal force acting on the box? Use [formul

Example 2 medium

A [formula] block rests on a ramp inclined at [formula] to the horizontal. What is the normal force

Example 3 medium

A [formula] box on a horizontal floor has a [formula] downward push applied to it. What is the norma

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