Chapter 1- Momentum And Energy Flashcards
Impulse eq
Impulse = force x time
Impulse unit
Newton seconds
N s
Impulse =
Change in momentum
Force =
Rate of change of momentum
Impulse shown on what type of graph
Force- time graphs
Impulse= area under the graph
Car safety calculations
Change in momentum when car is brought to rest produces an impulse Ft.
If we increase the time then the force will decrease increasing the safety of the passengers (for same mv)
Car safety precautions
Crumple zones
Seat belts
Air bags in front seats
Collisions where kinetic energy is not conserved
In elastic
Collisions where kinetic energy is conserved
Elastic
Work done by a force eq
Work= force x distance
Gravitational potential energy eq
mgh
Elastic potential energy eq
1/2 kx^2
Kinetic energy eq
1/2 mv^2
Types of mechanical energy
- GPE
- KE
- EPE
Mechanical energy sometimes appears to be lost to surroundings often as a result of…
Work done against contact friction or air resistance
Thermal energy of the particles of the surroundings is also called?
Internal energy
Principle of conservation of energy def
Energy can neither be created or destroyed: can only be transferred from one form to another
Eq combining kinetic energy and momentum
p= ✔️2mEk
Ek= p^2 / 2m
What is the speed of light in air
3 x10 ^8 m/s
Electron volt def
The energy gained by a particle of unit electronic charge when accelerated through a pd of 1 volt
1 eV = how many joules
1.6 x10^-19 J
What can be different even if kinetic energies are the same?
Momenta
Which type of diagram can be used to show loss of energy
Sankey diagram
Momentum in two dimensions what must equal the total forward momentum
For momentum to be conserved, the total forward momentum must equal the momentum vector totals
(The sum of the resolved momenta)
Force = the rate
Of change of momentum
What is the difference in eq between force and instantaneous force
F= m 🔺v/ 🔺t
Or
F= m dv/dt
Force equations the other way around
F= v 🔺m/ 🔺t
Or
F= v dm/dt
Water cannons are widely used in…
Crowd control
Alternative to
F= v 🔺m/ 🔺t
F = v^2 A ‘rho’
Simplified jet engine (3 part)
1) takes in cold air
2) heats up this air
3) throws out hot air
Doodlebugs bomb mechanics
Used all the fuel they carried by the end of the flight
Londoners could hear the engine cut out
Sudden silence meant a bomb was about to fall to the ground
