Unit 1- Mechanics and Materials Flashcards
This covers Unit 1 Physics content
What are the equations of motion for constant acceleration?
v=u+at, s=ut+ 0.5at^2, v^2=u^2+2as and s=(u+v)/2t.
Where u is initial velocity, v is final velocity, a is acceleration, t is time and s is displacement.
Define displacement and how it differs from distance
Displacement is the shortest distance from the initial to the final position in a specific direction, while distance is the total path traveled without regard to direction.
What is the significance of the area under a velocity-time graph?
The area under a velocity-time graph represents the displacement of an object.
State Newton’s First Law of Motion
It states that an object remains at rest or in uniform motion unless acted upon by an external force.
State Newton’s Second Law of Motion
The rate of change of momentum of an object is proportional to the applied force (f=ma)
State Newton’s Third Law of Motion
For every action, there is an equal and opposite reaction.
What is meant by the term resultant force?
The resultant force is the single force that has the same effect as all the forces acting on an object combined.
Define the conditions required for an object to be at equilibrium
The sum of all forces acting on the object must be zero (ΣF=0), and the sum of all moments about any point must also be zero (ΣM=0)
What is the formula for work done on an object?
Work = Force × Distance × cos(θ), where θ is the angle between the force and displacement direction.
How is Kinetic Energy calculated?
KE= 1/2mv^2, where m is mass and v is velocity
Define power.
Power is the rate at which work is done or energy is transferred.
Give the formula for power in terms of energy transfer.
P=E/t, where E is energy and t is time.
State the principle of conservation of energy.
Energy cannot be created or destroyed; it can only be transformed from one form to another, with the total energy in a closed system remaining constant.
Define momentum.
Momentum is the product of an object’s mass and velocity.
Provide the formula for momentum.
p=mv
Explain the difference between elastic and inelastic collisions
In elastic collisions, both momentum and kinetic energy are conserved. In inelastic collisions, momentum is conserved, but kinetic energy is not.
How is impulse related to momentum?
Impulse is the change in momentum of an object.
What is the formula for impulse?
FΔt=Δp
Define Stress
Stress is force per unit area
Give the formula for stress
(𝜎=f/a)
What is strain?
Strain is extension per unit length.
Give the formula for strain.
(𝜖=ΔL/L)
What does Young’s Modulus measure?
Young’s Modulus measures a material’s stiffness, calculated as the ratio of stress to strain.
What is the formula for Young’s Modulus?
E=σ/ϵ
How is the elastic limit of a material identified on a stress strain graph?
It is the point beyond which the material will no longer return to its original shape when the stress is removed.
What is the difference between brittle and ductile materials?
Brittle materials break without significant deformation (e.g., glass), while ductile materials can be stretched into a wire before breaking (e.g., copper).
Explain what is meant by tensile strength.
Tensile strength is the maximum stress a material can withstand while being stretched before breaking.
What is Hooke’s Law and how is it applied?
Hooke’s Law states that the force applied to a spring is directly proportional to the extension, provided the elastic limit is not exceeded
What is the formula for Hooke’s Law?
(F=kx)
How is the density of a material calculated?
density=mass/volume
Why do objects with the same volume but different masses have different densities?
Because density depends on both mass and volume; an object with greater mass in the same volume will have a higher density.
Define viscosity
Viscosity is a fluid’s resistance to flow.
How does viscosity affect motion of objects through a fluid?
higher viscosity means greater resistance to motion (e.g., honey vs. water).
State Stoke’s Law.
Stokes’ Law is the Drag Force (F)=6πηrv, where η is viscosity, r is radius of the object and v is velocity. It is used to calculate drag on small spherical objects moving through a viscous fluid.
