# Homework Help: Conservation of momentum - falling from hovering helicopter

1. Jan 1, 2013

### Hilarry

1. The problem statement, all variables and given/known data

Bronco dives from a hovering helicopter and finds his momentum increasing. Does this violate the conservation of momentum?

2. Relevant equations

p(before) = p(after)

3. The attempt at a solution

no, this does not violate the c.o.m, because it is a closed system of the helicopter and Bronco? or is it a system between Bronco and the earth?
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Jan 2, 2013

### haruspex

Which do you think it is? For the one you choose, what explains how momentum is conserved?

3. Jan 2, 2013

### Hilarry

conservation of momentum only occurs when no external forces are acting on the system, in this case, gravity is an external force affection the system, therefore increasing Bronco's momentum, his momentum is increasing while the momentum of the heli is constant, this breaks the conservation of momentum

Does this make sense?

4. Jan 2, 2013

### haruspex

The question asks about violation of the law. Since the law only applies to closed systems, any violation must be in a closed system. If gravity is involved, what must be included to make the system closed?

5. Jan 2, 2013

### Hilarry

I'm sorry, I just don't understand :/

6. Jan 2, 2013

### haruspex

Bronco is accelerating because of gravity. Will including the helicopter produce conserved momentum? Will including the Earth produce conserved momentum?

7. Jan 2, 2013

### PeterO

What makes you think the momentum of the helicoptor will remain constant?

For the Helicopter to be hovering before Bronco jumped, the pilot must have set the rotor angles and engine speed so that sufficient upward force was balancing the weight of the 'copter + Bronco.
Once Bronco jumped/fell out - what would happen to the 'copter if the pilot adjusted nothing?

Perhaps you could compare to Bronco being in the basket of a stationary Helium-filled balloon and jumping out - since the helicopter pilot would almost certainly react to the load change - due to his many years of training and experience.