What is the Difference Between Free Fall and Projectile Motion?

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The main difference between free fall and projectile motion lies in the dimensions of the motion and the influence of gravity. Here are the key differences:

  • Free Fall: This occurs when an object falls vertically under the influence of gravity, with no other horizontal forces acting upon it. The motion is one-dimensional, and the object accelerates only in the vertical direction. Examples of free fall include dropping a ball or a coin from a height.
  • Projectile Motion: This is a special case of free fall where an object is launched or thrown into the air with an initial horizontal velocity, causing it to move horizontally as it falls vertically. The motion is two-dimensional, and the object accelerates in both horizontal and vertical directions. Examples of projectile motion include throwing a ball, a shot put, or a ski jumper flying through the air.

To summarize, free fall is a one-dimensional motion where an object falls vertically under gravity, while projectile motion is a two-dimensional motion where an object is launched with an initial horizontal velocity and falls vertically while moving horizontally under gravity.

Comparative Table: Free Fall vs Projectile Motion

Here is a table comparing the differences between free fall and projectile motion:

Feature Free Fall Projectile Motion
Definition Free fall is the motion of an object under the influence of gravity only, with no initial velocity and no air resistance. Projectile motion is the motion of an object under any force field, with an initial velocity and possibly air resistance.
Initial Velocity Zero. Non-zero.
Force Field Occurs only under gravity. Can occur under any force field.
Air Resistance Free fall cannot occur in situations where air resistance is present; the object will reach a terminal velocity. Projectile motion can occur in situations where air resistance is present.
Acceleration Objects in free fall experience a constant downward acceleration of 9.81 m/s². Projectiles can experience a variety of accelerations depending on the force field and air resistance.
Maximum Height The maximum height of a free-falling object is determined by its initial height and the acceleration due to gravity. The maximum height of a projectile depends on the angle it was thrown, its initial velocity, and air resistance.

In summary, free fall is a special case of projectile motion where the initial velocity is zero and occurs only under gravity, while projectile motion can occur under any force field and with any non-zero initial velocity. Objects in free fall experience a constant downward acceleration due to gravity, while projectiles can experience variable accelerations depending on the force field and air resistance.