# Conservation of Linear Momentum of astronaut

• rmarkatos
In summary, the conversation discusses a scenario of an astronaut in outer space with a propulsion unit that ejects gas. The goal is to determine the mass of the ejected gas. After analyzing external and internal forces, it is concluded that the sum of the two velocities should equal zero. Using the initial conditions of the astronaut being motionless and labeling the astronaut and propulsion unit as m1 and m2 respectively, the equation 160kg(-30m/s) + m2(32m/s)=0 is derived. Solving for m2 results in a mass of 150kg.

#### rmarkatos

I am pretty sure i have this question correct but i want to make sure it is likely to show up on a test

An astronaut is motionless in outer space. Upon command the propulsion unit strapped to his back ejects some gas with a velocity of 32m/s and the astronaut recoils with a velocity of -30m/s. After the gas is ejected the mass of the astronaut is 160kg. What is the mass of the ejected gas?

well after looking at external and internal forces they should both equal zero.
So i found that Pf=Pi is that correct? But the initial conditions are zero because the astronaut was motionless in outer space. I am going to call m1 and vf1 the astronaut and m2 and vf2 the propulsion unit.

m1vf1+m2vf2=0

160kg(-30m/s) + m2(32m/s)=0
-4800kg m/s +m2(32m/s)=0
m2(32m/s)=4800kg m/s

solving for m2 i got 150kg. is that correct?

Yes, appears correct.

Your understanding of the conservation of linear momentum seems to be correct. The equation you used, m1vf1+m2vf2=0, is the correct representation of the principle. By setting the initial momentum (Pi) to zero, you are taking into account that the astronaut was initially motionless. Your calculation of m2, the mass of the ejected gas, also seems to be correct. This type of question is commonly used in tests and quizzes to assess students' understanding of the conservation of linear momentum. Keep up the good work!

## What is Conservation of Linear Momentum?

Conservation of Linear Momentum is a fundamental law of physics that states that the total momentum of a system will remain constant unless acted upon by an external force. This means that the total momentum of all objects involved in a system will remain the same before and after a collision or interaction.

## How does Conservation of Linear Momentum apply to astronauts?

Conservation of Linear Momentum applies to astronauts in space because they are in a closed system with no external forces acting on them. This means that their total momentum will remain constant, and any changes in momentum must be accounted for by changes in the momentum of other objects in the system.

## What are the implications of Conservation of Linear Momentum for astronauts in space?

The implications of Conservation of Linear Momentum for astronauts in space are that they must carefully control their movements and interactions with objects in order to conserve their momentum. Any sudden changes in momentum could have significant consequences, such as causing the astronaut to lose control or collide with other objects.

## How do astronauts maintain their momentum in space?

Astronauts maintain their momentum in space by carefully controlling their movements and interactions with objects. They can use tools and equipment, such as thrusters, to make small adjustments to their momentum when necessary. They can also use their own body movements, such as pushing off of surfaces, to change their momentum.

## What happens if the Conservation of Linear Momentum is violated in space?

If the Conservation of Linear Momentum is violated in space, it means that an external force has acted on the system. This could result in unexpected changes in momentum and potentially cause collisions or other accidents. In order to prevent this, astronauts must carefully monitor their movements and interactions to ensure that momentum is conserved at all times.