Energy and Momentum Flashcards
Work is responsible for the
Changing energy of an object
Impulse is responsible for the
Changing momentum of an object
Work is the measure of
Transferred mechanical energy
What is the unit for Work?
Joules
What is the equation for Work?
W = Fdcos0
Work is 0 when the force is
Perpendicular to motion
Work is negative when the force is
Opposite of the motion
What is the unit of Power?
Watts
What is the equation of Power?
P = W / t
Kinetic energy and potential energy are forms of
Mechanical energy
Mechanical energy is conserved when
Total energy is constant
Mechanical energy is not conserved with
Friction
The sum of Energy (E) =
K + U
The work-energy theorem states that the work performed by all the forces acting in a certain time interval result in the
Change in Kinetic Energy
What is the equation for the work-energy theorem?
W = ∆K = Kf - Ki
Conserved forces have associated
Potential energies
How is the force when the work required to move a particle in a round-trip is 0?
It is conservative
How is the force when the work required to move a particle between two points is the same, regardless of path?
Also conservative
Gravity is a
Conservative force
Nonconservative forces cause for energy to be
Transferred into another form
What are examples of nonconservative forces?
- Friction
- Air resistance
- Viscosity
Conservation of energy is when the total mechanical energy is
Constant
Constant mechanical energy is caused when
- Work by nonconservative forces = 0
- There are no nonconservative forces
What equations display constant total mechanical energy?
- E = K + U = constant
- ∆E + ∆K + ∆U = 0
What is the equation used for nonconservative systems?
W’ = ∆E = ∆K + ∆U
Nonconservative systems are when there is
Friction or air resistance present
Pulleys lift heavy weights with
Smaller forces over long distances
The load of the pulley is the
Weight, or the ∑Tensions in rope
The effort of the pulley is the
Force exerted when lifting
Efficiency is the
Measure of the amount of work put in and the work that comes out
What is the equation for efficiency?
Load * Load Dist / Effort * Effort Dist
What is the equation for momentum?
p = m * v
Impulse is the
Change in momentum
Impulse is measured in
Joules
Conservation of momentum is experiences when the
Net impulse of external forces on a system equals 0, making the total momentum constant
Conservation of momentum is automatic when there are
- No external forces
- ∑External forces = 0
For internal forces, how is momentum?
P initial = P final
What is the equation for a collision between two objects?
Pai + Pbi = Paf + Pbf
Completely inelastic collisions are ones in which
Colliding bodies stick after the collision
Completely inelastic collisions result in the
Combined mass of ma + mb
What is conserved in completely elastic collisions?
Both momentum and KE
