To find the horizontal distance of an object dropped from a plane, you need to take into account the object's initial height and the time elapsed since it was dropped. The formula for calculating horizontal distance (d) is:

```

d = v * t

```

Where:

* d = Horizontal distance (in meters or any unit of length)

* v = Horizontal velocity of the object (in meters per second)

* t = Time elapsed since the object was dropped (in seconds)

To determine the values for v and t:

1. Horizontal Velocity (v):

Assume that the plane is flying in a straight line at a constant horizontal velocity (v). This velocity can be obtained from the plane's specifications or measurements.

2. Time Elapsed (t):

Calculate the time (t) elapsed since the object was dropped. You can do this by measuring the time it takes the object to hit the ground using a stopwatch or other appropriate means. Alternatively, you can estimate the time using the object's initial height (h) and acceleration due to gravity (g) using this equation:

```

t = sqrt(2 * h / g)

```

Where:

- t = Time elapsed (in seconds)

- h = Initial height (in meters)

- g = Acceleration due to gravity (approximately 9.81 meters per second squared)

By substituting the values for v and t into the formula (d = v * t), you can determine the horizontal distance (d) covered by the object before hitting the ground.