9.5 Explosions

Question 1

When two objects fly apart after being initially at rest, they…

Answer 1

…recoil from each other with equal and opposite amounts of momentum so they move away from each other in opposite directions

Question 2

Why are alpha particles from a given isotope always emitted with the same kinetic energy?

Answer 2

Because they are emitted with the same speed, provided no external forces act. This is because each alpha particle and the nucleus that emits it move apart with equal and opposite amounts of momentum

Question 3

Why aren’t beta particles from a given isotope always emitted with the same kinetic energy?

Answer 3

Because a neutrino or antineutrino is emitted as well

Question 4

Model explosion setup:

Answer 4

Trolley A and B with a spring loaded bolt on one
A block on each side to stop trolleys
Distance travelled to point of impact with block is equal to speed*time taken
Distance ratio same as speed ratio as trolleys have equal amounts of momentum, the ratio of speeds s the inverse of the mass ratio Ie. If trolley A travels twice as far as B, then the mass of A must be half the mass of B