Answer:
The recoil speed of Astronaut A is 0.26 m/s.
Explanation:
Given that,
Mass of astronaut A, 
Mass of astronaut B, 
Astronaut A pushes B away, with B attaining a final speed of 0.4, 
We need to find the recoil speed of astronaut A. The momentum remains conserved here. Using the law of conservation of linear momentum as :

So, the recoil speed of Astronaut A is 0.26 m/s.
Answer:
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Explanation:
use and u will pass
A, Mechanical and A, Chemical.
Conservation of momentum: total momentum before = total momentum after
Momentum = mass x velocity
So before the collision:
4kg x 8m/s = 32
1kg x 0m/s = 0
32+0=32
Therefore after the collision
4kg x 4.8m/s = 19.2
1kg x βm/s = β
19.2 + β = 32
Therefore β = 12.8 m/s