# Momentum. resulting velocity. Rocket

• rtamplain
In summary, the problem involves an astronaut firing a 100 N rocket backpack for 2.0 seconds while weightless in space, and the resulting velocity of the astronaut and equipment is asked. Using the equation for momentum, the difference of momentum is calculated to be 200 kgm/s, and by setting this equal to the momentum of the astronaut and equipment (calculated using their weight on earth), the resulting velocity is found to be 1 m/s.
rtamplain
[SOLVED] Momentum. resulting velocity. Rocket

## Homework Statement

On earth, an astronaut and equipment weigh 1,960.0 N. While weightless in space, the astronaut fires a 100 N rocket backpack for 2.0 s. What is the resulting velocity of the astronaut and equipment?

I have to be missing something. I tried using every formula given to me in class and I cannot get anywhere. Please help. Thanks.

## Homework Equations

p=mv
Ft= (mf)(vf)-(mi)(vi)
Ft=ma+v(difference of m/t)
m1v1=m2v2

## The Attempt at a Solution

I tried a few and can't get a relevant answer. I really do not know where to begin with the rocket.

Last edited:
Don't worry about the rocket itself. You only care about what it does. It applies a constant force over a specified time? How does this affect the astronaut in terms of momentum?

difference of momentum= (100N)(2.0s) = 200kgm/s

200kgm/s= (1960N/ 9.8m/s^2) V

V=1m/s

I first found the difference of momentum which is force * time. then used the equation momentum=mass*velocity. Is this correct?

rtamplain said:
difference of momentum= (100N)(2.0s) = 200kgm/s

200kgm/s= (1960N/ 9.8m/s^2) V

V=1m/s

I first found the difference of momentum which is force * time. then used the equation momentum=mass*velocity. Is this correct?

Looks Good!

## What is momentum?

Momentum is a measure of an object's motion, calculated by multiplying its mass and velocity.

## How is momentum conserved?

Momentum is conserved in a closed system, meaning that the total momentum of all objects in the system remains constant, even if they collide or interact.

## What is the equation for calculating momentum?

The equation for momentum is p = m x v, where p is momentum, m is mass, and v is velocity.

## How does momentum affect an object's resulting velocity?

The greater the momentum of an object, the greater its resulting velocity will be after a collision or interaction.

## How is momentum related to rocket propulsion?

Rockets use Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. The fuel expelled from the rocket generates a force in the opposite direction, propelling the rocket forward with a significant amount of momentum.

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