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Newton's second law of motion

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Intros
Lessons
  1. Introduction to Newton's second law
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    Meaning of Newton's second law
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    Newton's second law formula
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    Newton, the unit of force
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Examples
Lessons
  1. Applying Newton's second law
    1. What is the unbalanced force required to accelerate a 1370 kg car at 4.25 m/s2m/s^{2}?
    2. What is the unbalanced force required to bring a 995 kg car travelling at 11.5 m/s to a stop in 30.0 m?
    3. An apple falls from a tree.

      i. What is the force of gravity acting on a falling 0.200 kg apple?

      ii. If the apple is accelerated downwards at 9.53 m/s2m/s^{2}, find the force of air resistance acting on the apple.

Topic Notes
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In this lesson, we will learn:
  • Newton's second law of motion
  • Problem solving with Newton's second law of motion

Notes:

  • Newton's second law: If a net force acts on an object, its velocity changes. The acceleration is proportional to the magnitude of the net force, and inversely proportional to the mass, or F⃗net=ma\vec{F}_{net}=ma
  • The force of gravity acting on an object is F⃗g=mg\vec{F}_{g}=mg, where gg is acceleration due to gravity (9.81 m/s2 [down])
Newton's Second Law

ΣF⃗=F⃗net=ma⃗\Sigma \vec{F} = \vec{F}_{net} = m\vec{a}

ΣF⃗:\Sigma \vec{F}: sum of all forces, in newtons (N)

F⃗net:\vec{F}_{net}: net force, in newtons (N)

m:m: mass, in kilograms (kg)

a⃗:\vec{a}: acceleration, in meters per second squared (m/s2)(m/s^{2})