physics 5.1 5.2

momentum

is defined as the product of mass and velocity p=mv unit: kg. m/s - "p" and "v" have a direct relationship, increases and decrease together

conservation of momentum

momentum is conserved meaning initial momentum=final momentum MaVa=MbVb (conservation of momentum) applying the conservation momentum MaVa+MbVb=(Ma+Mb)vc (common velocity) before colliosn=after collison -neg. signs indicates is moving in the opp. direction 3rd law forces equal and opposite msvs=mfvf

elastic collisons

when two objects collide and bounce off each other

center of mass

0-100 50 is the center of mass all collisons in this lesson are treated as center of mass collisons

Under what conditions is kinetic energy conserved in a collision?

An elastic collision is one where kinetic energy is conserved. The masses that collide don't deform from the collision nor do they stick together. An example of this would be pool balls colliding. Inelastic collisions occur when masses collide and stick together and/or there is deformation of either or both masses.

inelastic collisons: applying the conservation principle and momentum energy (kinetic energy)

MaVa+Mb(-Vbi)=(Ma+Mb)vf momentum is conserved kinetic energy not conserved 1/2MaVai^2 + Mb(-Vbi)^2=1/2(Ma+Mb)(Vf)^2

elastic collisons: applying the conservation of momentum and kinetic energy

MaVai +Mb(-Vbi)=MaVaf+MbVbf momentum is conserved 1/2MaVai^2+1/2Mb(-Vbi)^2=1/2Ma(Vaf)^2+1/2Mb(Vbf)^2 -kinetic energy is conserved

Is velocity conserved in a collision?

Momentum is conserved. Therefore velocity is not. ... When kinetic energy is transferred between portions of the system with different masses, the conservation of momentum forces the total velocity to change. Momentum is conserved, but internal kinetic energy is not conserved. ... (b) The objects stick together (a perfectly inelastic collision), and so their final velocity is zero.

Can you generate a collision wherein the total momentum changes? How?

Momentum is the product of a moving object's mass and velocity . ... When two objects collide the total momentum before the collision is equal to the total momentum after the collision (in the absence of external forces). This is the law of conservation of momentum. It is true for all collisions.

Do both cars always change speed by the same amount in a collision?

The two collisions are completely equivalent. From the point of view of one of the vehicles it makes absolutely no difference whether it hits a rock wall at 50 km/h or another identical vehicle which was traveling at the same speed in the opposite direction.

impluse

change in momentum I=ft

impluse-momentum

derived from Newton's 2nd law (f=ma) ft=m(vf-vi) f is inversley proportional to t when F increases vice versa