(7c4p133) A helicopter is flying in a straight line over a level field at a constant speed of 6.0 m/s and at a constant altitude of 10.6 m. A package is ejected horizontally from the helicopter with an initial velocity of 13.0 m/s relative to the helicopter, and in a direction opposite the helicopter's motion. Find the initial velocity of the package relative to the ground.

The package velocity with respect to the ground is -7 m/s, if we treat helicopter velocity direction as positive.

Explanation:

Velocity of the package relative to the ground is the sum of velocity vector of the package relative to the helicopter and the velocity vector of the helicopter relative to the ground.

Since these 2 vector are in opposite direction, we will pick the package velocity with respect to helicopter negative

= 6 fwd + 13 bwd = 6 fwd + (-13) fwd = -7 fwd or 7 bwd

So the package velocity with respect to the ground is -7 m/s, if we treat helicopter velocity direction as positive.