A billiard ball of mass m hits another one of the same mass. The first ball moves off at 30 degrees. For an elastic collision what are the velocities of both balls after the collision. In the lab frame where the second ball starts at rest, what angle compared to the direction of initial velocity of the first ball does the 2nd ball move?

Beryl states that insulation with the smallest possible thermal conductivity is best to keep a house warm in winter, but worst for keeping a house cool in summer. sapphire insists the reverse is true: low thermal conductivity is good in the summer, but bad in the winter. which one, if either is correct? a. beryl, because low thermal conductivity results in low heat transfer. b. beryl, because low thermal conductivity results in high heat transfer. d. sapphire, because low thermal conductivity results in high heat transfer. e. neither, because low heat transfer is desirable both in summer and in winter.