Acar of mass m moving at a speed v1 collides and couples with the back of a truck of mass 3m moving initially in the same direction as the car at a lower speed v2. (use any variable or symbol stated above as necessary.) (a) what is the speed vf of the two vehicles immediately after the collision? vf = (b) what is the change in kinetic energy of the car❝truck system in the collision? ? k =

Explanation:

Using the principle of conservation of momentum

momentum before the collision  =  momentum after the collision

Change in kinetic energy =  sum of kinetic energies after the collision -  sum of kinetic energies before the collision

The simplification for kinetic energy can be made by substitution the answer for the first part into the second part

28. evolution

29. environment, survive, offspring  

explanation:

b would be the answer