Maybe you can split up the questions. I will try to answer your first question.
1. In an elastic collision, momentum is conserved. The momentum before the collision is equal to the momentum after the collision. This is a consequence of Newton's 3rd law. (Action = Reaction)
2. Momentum: p = m₁v₁ + m₂v₂
m₁ mass of ball A v₁ velocity of ball A m₂ mass of ball B v₂ velocity of ball B
Momentum before the collision: p = 2*9 + 3*(-6) = 18 - 18 = 0
Momentum after the collision: p = 2*(-9) + 3*6 = -18 + 18 = 0
3: mv + m(-v) = m(-v) + m(v) the velocities would reverse.
4.This question is not factual since the energy of an elastic collision must also be conserved. The final velocities should be: v₁ = -1 m/s and v₂ = 5 m/s. That said assuming the given velocities were correct: before collision p = 10*3 + 5*(-3) = 30 - 15 = 15 after collision: p = 10*(-2) + 5 * v₂ = 15 v₂ = 7
Kinetic energy because of the wood plank is just still and not moving it’s potential but since it’s asking which one it doesn’t have it doesn’t have kinetic energy cause it’s not moving
D The student's conclusion shows experimental bias Just because most of nis classmates like puffed cereal ,it is inappropriate to conclude puffed cereal is better than oats cereal
