โšพ๏ธhonors physics review

Frictionless Inclined Plane

Written by the Fiveable Content Team โ€ข Last updated September 2025
Written by the Fiveable Content Team โ€ข Last updated September 2025

Definition

A frictionless inclined plane is a theoretical, idealized surface that has no friction, allowing objects to slide down it without any resistance. This concept is often used in physics to simplify and analyze the behavior of objects on inclined surfaces.

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5 Must Know Facts For Your Next Test

  1. On a frictionless inclined plane, the only force acting on the object is the force of gravity, which is parallel to the surface of the plane.
  2. The acceleration of an object sliding down a frictionless inclined plane is constant and equal to $g\sin\theta$, where $g$ is the acceleration due to gravity and $\theta$ is the angle of the inclined plane.
  3. The mechanical advantage of a frictionless inclined plane is equal to the ratio of the length of the inclined plane to its height, which is $\sec\theta$.
  4. The work done by the force of gravity on an object sliding down a frictionless inclined plane is equal to the object's weight multiplied by the vertical distance it travels.
  5. The potential energy lost by an object sliding down a frictionless inclined plane is equal to the work done by the force of gravity, which is converted into kinetic energy.

Review Questions

  • Explain the relationship between the angle of an inclined plane and the acceleration of an object sliding down it in the absence of friction.
    • On a frictionless inclined plane, the only force acting on the object is the force of gravity, which is parallel to the surface of the plane. The acceleration of the object is constant and equal to $g\sin\theta$, where $g$ is the acceleration due to gravity and $\theta$ is the angle of the inclined plane. As the angle of the inclined plane increases, the component of the gravitational force parallel to the surface also increases, leading to a higher acceleration of the object.
  • Describe the mechanical advantage of a frictionless inclined plane and how it is related to the angle of the plane.
    • The mechanical advantage of a frictionless inclined plane is equal to the ratio of the length of the inclined plane to its height, which is $\sec\theta$. This means that the force required to move an object up the inclined plane is reduced by a factor of $\sec\theta$ compared to lifting the object directly. As the angle of the inclined plane increases, the mechanical advantage also increases, allowing for the use of smaller input forces to move the object.
  • Analyze the energy transformations that occur when an object slides down a frictionless inclined plane.
    • When an object slides down a frictionless inclined plane, the potential energy lost by the object is equal to the work done by the force of gravity, which is converted into kinetic energy. The work done by the force of gravity is equal to the object's weight multiplied by the vertical distance it travels. Since there is no friction, all of the potential energy lost is transformed into kinetic energy, and the object's speed increases as it slides down the plane. This demonstrates the conservation of energy principle, where the total energy of the system remains constant.

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