click below
click below
Normal Size Small Size show me how
EK Physics 4
momentum, machines, radioactive decay
Question | Answer |
---|---|
momentum | measure of a moving object's tendency to continue along its present path; always conserved in isolated system; is a vector |
momentum equals | p = mv |
elastic collision | collisions where mechanical energy is conserved |
inelastic collision | when colliding objects lose some of their mechanical energy to internal energy |
impulse | change in momentum (J), shows that if time over which force is increased, the same change in velocity can be achieve w/ lower force |
impulse eqn | J = delta(p) = Favg*delta(t) where t is time |
machines | mechanical devices that reduce force when doing work, ex: ramp. lever, and pulley |
ramp | inclined plane, reduces force required to move object to height of h bc force req'd is only mgsin(theta) as opposed to mg |
lever | based on principle of torque where increasing lever arm reduces force req'd |
pulley | allow force to act over greater distance and do the same amt of work **remember that T is the same at every pt in the rope |
half life | length of time necessary for 1/2 of a given amount of a substance to decay |
alpha decay | helium nucleus (2 protons + 2 neutrons) |
beta decay | expulsion of electron |
positron emission | emission of positron (proton transformed into neutron) |
electron capture | capture of electron along with merging of e' with proton to create a neutron |
gamma ray | high frequency photon, no charge and does not change identity of atom of which it is given off |
rest mass energy | E = m*c^2 = latent energy w/in mass of object |
mass defect | the difference in masses of the nucleons before forming the nucleus and the measured mass of the nucleus - this mass is plugged into E=mc^2 to find binding energy |
fusion | combining of two nuclei to for single heavier nucleus |
fission | splitting of single nucleus to form 2 lighter nuclei |