Answers to Conceptual Questions on Projectiles in Physics

Answers to true or false conceptual questions on projectiles in Physics and equations of a projectile .

A projectile is launched. Assuming that air resistance is negligible, which of the following are true?

  1. Any object upon which the only acting force is the force of gravity is called a projectile.

    TRUE: Definition

  2. The projectile problem involves constant velocity along the horizontal direction and constant acceleration along the vertical direction.

    TRUE: see equations of velocity and acceleration of projectile

  3. The vertical component of the velocity of the projectile is constant.

    FALSE: see equations of velocity of projectile.

  4. The horizontal component of the velocity of the projectile is constant.

    TRUE: see equations of velocity of projectile.

  5. The acceleration is constant.

    TRUE: see equations of acceleration of projectile

  6. The kinetic energy of the projectile is constant.

    FALSE: The magnitude of the velocity of a projectile is not constant, therefore its kinetic energy is not constant.

  7. The potential energy of the projectile is constant.

    FALSE: The height of the projectile changes and therefore the potential energy due to gravitation in not constant.

  8. The sum of the kinetic and potential energies is constant.

    TRUE: The total mechanical energy is constant.

  9. The minimum speed of the projectile is equal to horizontal component of the velocity of the projectile.

    TRUE: The velocity has two components: Vy and Vx. Vx is constant and Vy is a function of time and may be zero.

  10. The horizontal component of the velocity of the projectile varies linearly with time.

    FALSE: It is constant.

  11. The horizontal component of the displacement of the projectile varies linearly with time.

    TRUE: x = Vx t (see equations of displacement of projectile)

  12. The vertical component of the displacement of the projectile varies linearly with time.

    FALSE: y = Vy t - (1/2) g t2 (see equations of displacement of projectile)

  13. The path of a projectile is a parabola.

    TRUE: See equation of the path of a projectile.