Theme A Flashcards
What is mass the measure of?
Mass is the measure of an objects inertia, its resistance to changing its motion.
State the equation for density.
ρ = m / V
Where:
ρ = density
m = mass
V = volume
For a given substance, density is constant.
What type of force is weight?
Weight is the gravitational force between an object and the planet it is on; a non-contact force.
What base SI units make up a Newton.
Kg⋅m⋅s⁻²
State the relation between weight and mass.
F = m⋅g
Where:
F = force, weight
m = mass
g = acceleration due to gravity; 9.8 m⋅s⁻²
When is an object in translational equilibrium?
When the vector sum of all forces acting on an object is zero.
What is the normal force?
The force in the direction perpendicular to the surface when the object is in contact with a surface.
This force is equal to whatever is necessary for the object to not pass through the surface.
What is tension?
The force transmitted through an object when two ends are pulled apart.
Any arbitrary point within the object will feel two equal and opposite tension forces pulling it apart.
State the formula for buoyant force?
F = ρ⋅V⋅g
Where:
ρ = density of the fluid
V = volume of submerged portion of the object
g = acceleration of free fall
What determines whether an object will float in water or not?
If an object is more dense than the fluid that it is in, it will sink; and float if less dense.
State Hooke’s law
F = -k⋅x
Where:
x = length that the spring is deformed
k = spring constant / stiffness
Differentiate between elastic and plastic deformations in springs.
Elastic deformations: Deformations that aren’t permanent.
Plastic deformations: Deformations that are permanent.
Differentiate between static friction and dynamic friction.
Dynamic friction: The two surfaces are sliding.
Static friction: The two surfaces aren’t sliding.
State the equation of dynamic friction.
Ff = μd⋅Fn
Where:
Ff = force of friction
μd = coefficient of dynamic friction
Fn = normal force between the surfaces
State the equation of static friction.
Fs ≤ μs⋅Fn
Where:
Fs = force of friction
μs = coefficient of static friction
Fn = normal force between the surfaces
What is friction independent of.
The area of the surfaces in contact and the velocity that the surfaces slide.
State stoke’s law.
Fd = 6⋅π⋅η⋅r⋅v
Where:
η = viscosity of the fluid
r = radius of the sphere
v = velocity that the sphere falls through the fluid
State newtons first law of motion.
An object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force.
Thus an object in translational equilibrium will undergo no acceleration.
State newtons second law of motion.
F = m⋅a
Where:
F = force
m = mass
a = acceleration
State newtons third law.
Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first.
State the formula for work.
W = F⋅s⋅cosθ
Where:
W = work done
F = force
s = displacment
θ = angle between force and displacement
State the unit of work and what it is in base SI units
Joule
Newton meter
Kg⋅m²⋅s⁻²
In what graph is work the area of
Force displacement graph
State the work-energy theorem
W = ∆E
Where:
W = work
∆E = change in energy
