1 (1 point) In a closed system, what does the law of conservation of momentum explain? Question 1 options: The total momentum is constant The total momentum is always conserved at zero The total momentum is equal to the net external force The total momentum will constantly decrease Question 2 (1 point) How does a force sustained over a long time differ from the same force applied briefly? Question 2 options: Force sustained produces greater change in momentum Force sustained produces greater change in impulse Force sustained produces less change in momentum Force sustained produces less change in impulse Question 3 (1 point) How do you calculate whether a collision is inelastic or not? Question 3 options: Initial kinetic energy = Final kinetic energy Initial velocity = Final velocity Mass₁ * Velocity₁ = Mass₁ * Velocity₁ + Mass₂ * Velocity₂ cos₁ = cos₂ Question 4 (1 point) Which of the following is characteristic of elastic collision? Question 4 options: The total kinetic energy of the bodies before and after the collision is equivalent Atoms do not undergo elastic collisions when they collide Molecules undergo essentially elastic collisions when they collide Kinetic energy is converted into other forms of energy