can someone help me to solve these physics problems?

[becky z]

1)a neutron collides head-on with a carbon-12 nucleus. what is the ratio of the neutron's kinetic energy after the collision to that before the cllision?how many collisions are necessary to reduce the nrutron's energy by a factor of 10^6?

2)a uranium nucleus (at rest)fissions into two fragments, one is about 1/3 of the mass of the uranium, the other about 2/3. the lighter fragment recoils the speed of 1.7*10^7 m/s (thsi is about 1/18 of the speed of light). what is the speed of the other fragment? the mass of the ranium is 3.9*10^(-25) kg. find the total energy released in the fission of one nuclues.

can someone help me? thank u .
the answer for 1) is 91, 2) is 2.82*10^(-11) J