Who among the following concluded that an object moving on a frictionless horizontal plane must neither have acceleration nor retardation, i.e., it should move with constant velocity?

The correct answer is Galileo.

Key Points

• Galileo Galilei, a renowned Italian physicist and astronomer, laid the foundation of the concept of inertia, which later became a cornerstone of Newton's First Law of Motion.
• He proposed that an object moving on a frictionless horizontal plane would continue to move at a constant velocity unless acted upon by an external force.
• This idea challenged the Aristotelian view that an external force is always required to maintain motion.
• Galileo's experiments with inclined planes helped him formulate the idea that resistance (e.g., friction) is what causes objects to slow down, not an inherent tendency to stop.
• His pioneering work on the laws of motion directly influenced Isaac Newton's formulation of classical mechanics.

Additional Information

• Inertia:
  • Inertia is the property of an object to resist changes to its state of motion or rest.
  • This concept was first systematically studied by Galileo and later refined by Newton.
• Newton's First Law of Motion:
  • Also known as the Law of Inertia, it states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force.
  • This law builds on Galileo's observations and experiments.
• Friction:
  • Friction is a force that opposes motion between two surfaces in contact.
  • Galileo identified friction as the primary reason why objects eventually come to rest in the real world.
• Galileo's Inclined Plane Experiment:
  • Galileo used inclined planes to slow down the motion of objects, allowing him to study their behavior more carefully.
  • These experiments demonstrated that objects accelerate uniformly when rolling down a slope, leading to his insights on motion.
• Transition from Aristotelian Physics:
  • Aristotle believed that continuous force was required for motion, a view disproved by Galileo's work.
  • Galileo's ideas marked the beginning of the shift to modern physics.