AP Physics 1 Question 77: Answer and Explanation

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Question: 77


The graph above shows the velocities of two objects undergoing a head-on collision. Given that Object 1 has 4 times the mass of Object 2, which type of collision is it?

  • A. Perfectly elastic
  • B. Perfectly inelastic
  • C. Inelastic
  • D. Cannot be determined

Correct Answer: A


A First, perfectly inelastic can be immediately eliminated because the objects have different velocities after the collision. Next, recall that a collision is perfectly elastic if kinetic energy is conserved.

Because kinetic energy was conserved, the collision must be perfectly elastic.