⚛️ Physics Quiz 3: Newton’s Laws and Free-Body Diagrams

⚛️ Physics · Quiz 003

Connect motion to forces through free-body diagrams and Newton's three laws, then combine multiple forces to predict acceleration.

Learning goalConnect changes in motion to net external force and introduce free-body diagrams as the standard representation for dynamics.

  • 5 questions
  • Foundation
  • Explanations after finishing
Answered 0/5
FoundationWhich description best defines a free-body diagram for a selected object?
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Focus on the selected object and include forces acting on it, not forces it exerts elsewhere.

UnderstandingIn an inertial frame, an object moves in a straight line at constant velocity. What does Newton's first law imply about the net external force on it?
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Constant velocity means both speed and direction remain unchanged.

ApplicationA net horizontal force of 12 N acts on a 3.0 kg cart. What is the cart's acceleration?
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Use Newton's second law with the net force and the object's mass.

InterpretationA runner pushes backward on the ground and accelerates forward. Which pair is a Newton's-third-law interaction pair?
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A third-law pair consists of forces from the same interaction acting on two different bodies.

ConnectionA 10 kg crate experiences a 50 N horizontal force to the right and a 20 N horizontal force to the left. Its vertical forces balance. What is the crate's acceleration?
Need a small nudge?

Combine the horizontal forces first, then apply Newton's second law.

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