Conservation of linear momentum and acceleration due to gravity.

[vkash]

Homework Statement

A 1000,000 Kg aircraft drops a 1000 Kg packages of supplies over the surface of the earth. what approximate force felt by 100 Kg pilot at the instant of release.
(a) 1N
(b) 0.1N
(c) 10N
(d) zero

Homework Equations

anything you can think of.

The Attempt at a Solution

In starting aircraft is flying with constant speed. There is a constant downward force(mg) and a constant upward force by wings of plane applied. At the moment the package is dropped, Required force to maintain that height is decreased(since considerable mass decrease) but engines are still applying same amount of thrust so it will little move in upward direction. This extra force should equal to 1,000*9.8(weight of package). instantaneous acceleration of plane in upward direction is ~0.01. so upward force on the pilot will 100*0.01=1. That's what i think.
Where am i wrong?

 

[ehild]

Doesn't the pilot feel gravity?

ehild

 

[vkash]

Doesn't the pilot feel gravity?

ehild

yes.
So it should sum up to g+1 m/s².

 

[ehild]

An aircraft usually does not fly vertically upwards. We can assume that it flies horizontally. The upward force acting on the wings is about proportional to square of the speed. There is acceleration in the horizontal direction, but the speed is the same just after releasing the package than before.

ehild

 

[vkash]

An aircraft usually does not fly vertically upwards. We can assume that it flies horizontally. The upward force acting on the wings is about proportional to square of the speed. There is acceleration in the horizontal direction, but the speed is the same just after releasing the package than before.[/color]

ehild

How?

 

[PeterO]

Homework Statement

A 1000,000 Kg aircraft drops a 1000 Kg packages of supplies over the surface of the earth. what approximate force felt by 100 Kg pilot at the instant of release.
(a) 1N
(b) 0.1N
(c) 10N
(d) zero

Homework Equations

anything you can think of.

The Attempt at a Solution

In starting aircraft is flying with constant speed. There is a constant downward force(mg) and a constant upward force by wings of plane applied. At the moment the package is dropped, Required force to maintain that height is decreased(since considerable mass decrease) but engines are still applying same amount of thrust so it will little move in upward direction. This extra force should equal to 1,000*9.8(weight of package). instantaneous acceleration of plane in upward direction is ~0.01. so upward force on the pilot will 100*0.01=1. That's what i think.
Where am i wrong?

Just checking ... you gave the plane mass as 1000,000 kg. Did you mean 1,000,000 kg or should it have been 100,000 kg.
That would result in about 10N, using your initial reasoning, which I liked.

 

[vkash]

Just checking ... you gave the plane mass as 1000,000 kg. Did you mean 1,000,000 kg or should it have been 100,000 kg.
That would result in about 10N, using your initial reasoning, which I liked.

Oh sorry; mass of aircraft is 100,000 Kg.
How it is. it should g+1=10.8.

 

[ehild]

Oh sorry; mass of aircraft is 100,000 Kg.

In this case, you get a magnitude higher acceleration and force.
Although the pilot always feels gravity, I think the question refers to the extra force the pilot notices when the package is released.

ehild