Physics ch 3.7?

Question

A supply plane needs to drop a package of food to scientists working on a glacier in Greenland. The plane flies 120 m above the glacier at a speed of 100 m/s

How far short of the target should it drop the package?

Answer 1

Since the plane is moving, when the packet is released, it will move with the same horizontal velocity as the plane due to inertia.

So it will show projectile motion.

Solve for vertical and horizontal motions separately :

Vertical motion :

u = 0 m/s                       (as it has no initial velocity in the vertical direction)

a = - 10 m/s                   (- indicates that it is in the downward direction)

s = - 120 m

s = ut + 1/2*at^2

t = +/- 4.9 s

Time cannot be -ve.

So t = 4.9 s

Horizontal motion :

v = 100 m/s

t = 4.9 s

s = vt = 490 m

So the packet should be dropped when the plane is at a horizontal distance of 490 m from the target.

Total distance from the target = sqrt.(120^2 + 490^2) = 504.5 m

Hope this helps.

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