Momentum and Energy Flashcards
Momentum and its formula
a vector quantity of motion of a moving body, measured as a product of its mass and velocity. Given by p=mv
Conservation of momentum and its formula
States that any interaction or collision between two or more bodies in an isolated system does not change the total momentum. Meaning initial momentum will be equal to final momentum. Given by Pi=Pf
Define Impulse and its formula
Impulse is a measure of the change in momentum when two objects interact due to a force acting over time. Given by the formula I=Δp=mΔv
What direction will the impulse be?
The direction of an impulse will always be in the same direction as momentum and velocity.
Transpose Impulse formula with Newtons second law
Newtons 2nd law is given by F=ma which can be transposed with I=Δp=mΔv and give mΔv=FΔt and simplified to I=FΔt
What Ui units can impulse me measured in?
kgm2^-1 or N s
collision
the coming together of two or more objects where each object exerts a force on the other
impulse
the change in momentum of a body as the result of a force acting over a time (vector quantity)
isolated system
A collection of interacting objects for which there is no external exchange of mass and energy
energy
a scalar quantity describing the ability to cause a physical change
kinetic energy
Kinetic the energy of an object due to its motion
power
Power is the rate of change in energy with respect to time
work
Work the change in energy caused by a force acting on an object in a direction parallel to its motion
Kinetic formula
KE = 1/2mv2
Define work as a change in energy and the given formula
Work is a measure of the change in energy caused by a force. If given the energy of an object at two different locations. Given in the formula W = ΔKE
Work as the product of a force and displacement formula and what this means on an object
W=FS This means It is equivalent to stating that the kinetic energy of an object can change only when a force is applied parallel to the object’s motion so it either speeds up or slows down.
What are three situations where work is done by a constant force:
- If the distance moved is in the same direction as the applied force, energy is transferred to the object. This means the final energy (and speed) is greater than the initial energy (and speed).
- If the distance moved is in the opposite direction to the applied force, energy is transferred from the object. This means final energy (and speed) is less than the initial energy (and speed). The work done will have a negative value.
- If the distance moved is perpendicular to the applied force, no work is done (W = 0).
Define kinetic energy of an object and its formula
An object’s kinetic energy is the energy resulting from its motion. Kinetic energy is defined as: KE = ½mv2 where m is the object’s mass and v is its speed. The units of kinetic energy are Joules, just like all other forms of energy.
the principle of conservation of energy .
The principle of conservation of energy states that, in the absence of dissipative forces, a system’s total mechanical energy is constant. Dissipative forces such as friction or air resistance will decrease a system’s total mechanical energy
Force
The net force that an object is experiencing, is its current acceleration times its mass. Force can also be thought of as the change in momentum per unit time, or mass times the change in velocity per unit time. The SI unit of force is the Newton (N), 1N = 1 kg*m/s2
Define energy
energy a scalar quantity describing the ability to cause a physical change
Define Kinetic Energy
kinetic energy the energy of an object due to its motion
Define Power and its given formula
Power the rate of change in energy with respect to time/ P = ΔE/Δt where P = power (W), E = energy (J), t = time (s).
Power can also be viewed as the rate of work being done (P = W/Δt) when the change in energy is caused by a force.
Elastic collision
elastic collision a collision in which kinetic energy is conserved
Define energy dissipation
energy dissipation the transfer of energy out of a system
Define inelastic collision
inelastic collision a collision in which kinetic energy is not conserved
What collision is it when kinetic energy is conserved.
Elastic collisions. This means that the total kinetic energy of the colliding objects before the collision is equal to the total kinetic energy of the objects after the collision.
Define gravitational potential energy and its formula
Gravitational potential energy the stored energy associated with the position of an object in a gravitational field. Given formula ΔGPE = mgΔh
Conservation of energy
The initial energy equals the final energy of the system. For a system involving only kinetic energy and gravitational potential energy this gives us: KEi + GPEi = KEf + GPEf . Given by the formula:
Define compression (spring)
compression (spring) the process of decreasing an object’s length
Define extension
extension the process of increasing an object’s length
Define an idea spring
An ideal spring a spring that obeys Hooke’s law so that the force it exerts is proportional to its change in length
Define natural length in relation to a spring
natural length the length of a spring when no external forces are acting on
Define spring constant
spring constant a value that describes the stiffness of a spring
Define strain potential energy
strain potential energy the energy stored by the deformation of an object; also known as elastic potential energy or spring potential energy
Define Hookes law and its given formula
Hooke’s law describes the linear relationship between the force and displacement of an ideal spring. The spring constant, k, represents the stiffness of spring and determines the amount of force needed to compress or extend a spring. Given formula is Fs = −kΔx
Fs = spring restoring force (N), k = spring constant (N m−1), Δx = displacement from natural position (m)
Equilibrium involving springs
For an object attached to a vertical spring, when the force due to gravity acting on the object has the same magnitude as the restoring force of the spring (mg = kΔx), the net force on the object is zero. This is called the equilibrium position.
How is strain potential energy calculated?
What is strain energy also known as?
Elastic potential energy or spring potential energy.
The formula of conversation of energy:
KEi+GPEi+SPEi=KEf+GPEf+SPEf
This means: Initial Kinetic energy, gravitational and strain energy equal the final kinetic gravitational and strain energy.
Equilibrium position (spring-mass system)
equilibrium position (spring-mass system) the position of the mass at which the net force on the mass is zero. This position is always halfway between the two extreme points (endpoints) in oscillatory motion
Oscillate
move repetitively around a fixed position
Spring-mass system
spring-mass system the combination of a spring and a mass that is attached to one end of the spring
Energy conservation for a vertical spring-mass system
When does the mass come to a stop
At the top and bottom of an oscillation, the mass momentarily comes to a stop
Where is the equilbrium position?
– halfway between the top and bottom positions of the oscillating spring.
– where kΔx = mg.
– where a mass will eventually come to rest over time, as energy is dissipated.
