Lecture 3_190606 Flashcards
Newton’s Laws
1) on object in motion stays in motion … at rest stays….
2) until acted on by a force, F(N) = m(kg)*a(m/s^2)
3) for every action there is an equal and opposite reaction
Mass (kg)
m = F(N)/a(m/s^2)
Velocity (m/sec)
v = Δx/Δt
Acceleration (m/sec2)
a = Δv/Δt
Force (kg * m/sec2)
F = m * a
Scalars
magnitude and units, but NOT direction
- distance
- speed
- mass
Vectors
magnitude, units, and direction
- displacement
- velocity
- weight
Fundamental forces
1) nuclear force (strongest)
2) electromagnetic force
4) gravitational force (weakest)
Nuclear force
Strongest
Holds protons & neutrons together in nucleus
Electromagnetic force
Holds electrons in atoms, tries to force protons apart
Gravitational force
Weakest
Holds earth in sun’s orbit and keeps you from floating away
Gravitational constant & Gravity
F.earth = G * m.earth * m / r.earth^2
g ~ 9.8m/s^2
lb vs kg
lb = force
kg = mass
2.2 lb / kg
N
= kgg = kgm/s^2 = force
Scales
measure weight
Balances
measure mass