Collisions, Explosions and Impulse Flashcards
what does the momentum of an object depend on?
its mass and velocity
units of momentum
kgms-1
is momentum a scalar or vector?
vector so requires a direction
law of conservation of momentum
the total momentum before a collision is equal to the total momentum after a collision in the absence of external forces
law of conservation of energy
energy is always conserved
it cannot be created or destroyed
what may kinetic energy be converted into in a collision?
heat and sound
elastic collision
both momentum and kinetic energy are conserved
inelastic collision
only momentum is conserved, Ek is not
how to prove a collision is inelastic
Ek before>Ek after
if an object is travelling in the opposite direction what must you remember?
negative
impulse formulas
change in P=mv-mu
Ft=mv-mu
unit of impulse
Ns or Kgms-1
how to find impulse from a F-t graph
area under graph
what is the momentum normally before an explosion
0kgms-1
what happens if time of contact increase
average force exerted decreases
impulse stays the same so area under graph stays the same
