Answer:
-0.832 m/s²
Step-by-step explanation:
Since acceleration a = (v - u)/t where u = initial velocity of astronaut = +14.7 m/s (positive since he is moving towards the right), v = final velocity of astronaut = +4.8 m/s (positive since he is moving towards the right) and t = time taken for velocity change = time interval = 11.9 s.
Since a = (v - u)/t
Substituting the values of the variables into the equation, we have
a = (v - u)/t
a = (+4.8 m/s - (+14.7 m/s))/11.9 s
a = (4.8 m/s - 14.7 m/s)/11.9 s
a = -9.9 m/s ÷ 11.9 s
a = -0.832 m/s²
So, the astronaut's average acceleration is -0.832 m/s²