Practice question · Select all that apply
Select every statement that is TRUE about collisions in an isolated system.
Hints
- Sort the claims by which quantity they concern before judging them.
- One option contradicts the definition of inelastic.
Show the answer
- A. Total kinetic energy is the same before and after in an elastic collision
- B. Total momentum is the same before and after
- D. Momentum conservation follows from the third law's equal and opposite internal forces
- E. Objects that stick together have lost some kinetic energy
Why
Momentum survives every collision because the internal forces cancel in pairs. Kinetic energy survives only elastic ones by definition, so the inelastic claim is false and the sticking case always loses energy to heat and deformation.
Practise Momentum and Collisions
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