Newton's first law (inertia) Transitional Reasoning Practice

Questions

1. 1.

   During a physics demonstration, an automated cart moves along a straight, level track at a constant horizontal speed of 1.5 m/s. While the cart maintains this steady motion, a launcher mounted vertically on the cart fires a small steel sphere straight upward into the air. Assuming air resistance is negligible, which statement correctly predicts where the sphere lands relative to the cart and explains this outcome using Newton's first law?

   • A) It lands directly back into the launcher because no horizontal force acts on the airborne sphere, so it retains the cart's horizontal velocity throughout its flight.
   • B) It lands behind the launcher because once the sphere leaves the cart, a continuous forward force is required to maintain its horizontal motion.
   • C) It lands behind the launcher because the vertical impulse from the spring mechanism removes the sphere's forward momentum upon release.
   • D) It lands ahead of the launcher because the airborne sphere encounters zero friction while the cart experiences track resistance that slows its progress.
2. 2.

   A small puck on a frictionless horizontal air table is attached to a central peg by a light cord and moves in a horizontal circular path at a constant speed of 2.5 m/s. At the precise moment the puck is traveling due north, the cord breaks cleanly. According to Newton's first law of motion, how will the puck move immediately after the cord breaks?

   • A) It spirals outward with a gradually increasing radius and decreasing speed until it comes to rest.
   • B) It moves in a straight line directly away from the central peg in a purely outward radial direction at 2.5 m/s.
   • C) It moves in a straight line due north at a constant speed of 2.5 m/s across the table.
   • D) It continues along the curved circular path for a short distance before slowing down and stopping.
3. 3.

   A deep-space research probe travels through interstellar space far from any celestial bodies at a constant velocity of 15,000 m/s with all its engines shut off. Mission controllers fire a lateral thruster perpendicular to the probe's trajectory for 4.0 seconds to adjust its course, after which the thruster is completely deactivated. Neglecting any external resistive forces, which statement correctly describes the motion of the probe after the thruster is turned off?

   • A) It gradually curves back toward its original heading because its initial forward momentum reasserts itself.
   • B) It continues along the new heading but gradually decelerates because a continuous force is required to sustain motion.
   • C) It moves in a straight line along a new heading at a constant speed greater than its original speed.
   • D) It immediately reverts to its original straight-line path because the lateral force is no longer present.

Answers and step-by-step solutions appear after you finish the test.