Untitled Flashcards Set

Forces - balanced and unbalanced

• Force = a push or pull that acts on an object

  • Can cause an object ot move/accelerate

    • By changing speed/direction

• Balanced forces = same number of newtons pushing on each side of an object

• Unbalanced forces = different number of newtons pushing on each side of an object

• Object going at constant speed = balanced forces

• Object changing speeds = unbalanced forces

Calculating net force (and units)

• Fɴ=F1+F2

  • Ex: 165N -> 💟 <-28N(friction)

  • -> = positive

  • <- = negative

    • Fɴ= 165N -28N

    • Fɴ=137N

  • Ex: 120N -> 💟 -> 140N

    • Fɴ=120N + 140N

      • Fɴ= 260N

• Inputs and outputs = the sum of all forces on you

• When netforce is 0, it does not mean there is no force being applied, it just means the forces are equal

Newton’s First Law  (be able to state in words and understand)

Newton’s First Law (be able to state and apply to situations)

• Newton’s First Law of Motion = An object at rest tends to stay at rest unless acted upon by an unbalanced force, an object in motion tends to stay in motion unless acted upon by an unbalanced force

Significant Figures - counting and using in calculations

• All digits from 1-9 are significant

• All sandwiched 0s are significant

• Leading 0s are never significant

• Ending 0s are only significant when there is a decimal

Unit Conversions

Acceleration a = (v2-v1)/t     (know units)

 a = (v2-v1)/tf-ti

V = velocity (m/s)

t= time (s)

Newton’s Second Law (be able to state in words and understand relationships)

Newton’s second law = acceleration is directly proportional to net force and inversely proportional to mass

• Mass and force are proportional

F=ma (know units)

F= force (N)

M = mass ( kg)

a= acceleration (m/s^2)

Motion graphs

Newton’s Third Law

• For every action there is an equal and opposite reaction

  • Action and reaction force are always equal

Relationship between Newton’s 2nd and 3rd Laws

• Newton’s 3rd law says that every action has an equal and opposite reaction, meaning they have the same force, but Newton’s second law says that the consequence can be greater due to differences in mass

  • Ex: One person rolls a greater distance on a skateboard than the other when pushed off each other due to differences in masses