Newton's second law of motion

Newton's second law of motion

Lessons

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 Fnet=ma\vec{F}_{net}=ma
  • The force of gravity acting on an object is Fg=mg\vec{F}_{g}=mg, where gg is acceleration due to gravity (9.81 m/s2 [down])
Newton's Second Law

ΣF=Fnet=ma\Sigma \vec{F} = \vec{F}_{net} = m\vec{a}

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

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

m:m: mass, in kilograms (kg)

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

  • Introduction
    Introduction to Newton's second law
    \cdot
    Meaning of Newton's second law
    \cdot
    Newton's second law formula
    \cdot
    Newton, the unit of force

  • 1.
    Applying Newton's second law
    a)
    What is the unbalanced force required to accelerate a 1370 kg car at 4.25 m/s2m/s^{2}?

    b)
    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?

    c)
    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.