Answer:
Magnitude of Deceleration of the box is 1.5 m/s²
Explanation:
Let acceleration be "a"
Initial Speed (u) = 5 m/s
Final Speed (v) = 4 m/s
Distance travelled (s) = 3 m
We know, v²-u²=2as
So,
4²-5²=2×a×3
16-25=6×a
-9=6×a
-9/6=a
a=-9/6
a=-3/2
a=-1.5