AP Physics C: Mechanics 2.3 Newtons Third Law Questions

Analyse interactions between two objects by pairing equal and opposite forces or impulses and distinguishing those pairs from forces that balance on one object.

Syllabus
Effective Fall 2024
Course
AP Physics C: Mechanics

Exam points

  • represent an interaction as equal and opposite forces acting on two different objects
  • distinguish third-law pairs from forces that happen to balance on a single object
  • apply paired-force or paired-impulse reasoning to contacts, ropes, friction, and collisions

Question 1

[Maximum number: 2]

Cart 1 of mass m1m_{1} is held at rest above the bottom of an incline. Cart 2 has mass m2m_{2}, where m2>m1m_{2}>m_{1}, and is at rest at the bottom of the incline. At time t=0, Cart 1 is released and then travels down the incline and smoothly transitions to the horizontal section. The center of mass of Cart 1 moves a vertical distance of H, as shown. At time tCt_{\mathrm{C}}, Cart 1 reaches the bottom of the incline and immediately collides with and sticks to Cart 2. After the collision, the two-cart system moves with constant speed v. Frictional and rotational effects are negligible.

During the collision, is the impulse on Cart 1 from Cart 2 greater than, less than, or equal to the magnitude of the impulse on Cart 2 from Cart 1 ?

Greater than Less than Equal to

Justify your answer.

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