Question

CSA 80kg astronaut carrying a 5kgfire extinguisher is floating inspace in the same spot. How fastwill the astronaut move if theastronaut throws the fireextinguisher with a speed of5m/s.

Answer 1

We know that the mechanical energy has to be conserved, this means that in an isoleted system we have that:

`K+U=0`

where K is the kinetic energy and U is the potential energy. Since we are in space the potential energy is zero. Then we have that:

`K=0`

Now, remember that the kinetic energy is equal to:

`(1)/(2)mv^2`

In this case we have that the conservation of energy means:

`(1)/(2)m_av^2_a=(1)/(2)m_bv^2_b`

Then:

`\begin{gathered} (1)/(2)(80)v^2_a=(1)/(2)(5)(5)^2 \\ v_a=\sqrt[]{(5^3)/(80)} \\ v_a=1.25 \end{gathered}`

Therefore the velocity of the astronaut is 1.25 m/s