I think it is A) but someone might need to double check that.
see i was trying to figure out the answer but i didn't understand it so i took the time to research and work it out but i still didn't understand i found one that was close to it and i got the same one as the other person which is D but idk if it is that type of question if it is than it is d if not then idk
Answer:
Coefficient of friction = 0.5
Explanation:
Given:
Mass of box = 5 kg
Force applied = 20 N
Acceleration = 2 m/s²
Find:
Coefficient of friction
Computation:
Friction force = Mass x Acceleration.
Friction force = 5 x 2
Friction force = 10 N
Coefficient of friction = Friction force / Force applied
Coefficient of friction = 10 / 20
Coefficient of friction = 0.5
Answer:

Explanation:
We could use the following suvat equation:

where
s is the vertical displacement of the coin
v is its final velocity, when it hits the water
t is the time
g is the acceleration of gravity
Taking upward as positive direction, in this problem we have:
s = -1.2 m

And the coin reaches the water when
t = 1.3 s
Substituting these data, we can find v:

where the negative sign means the direction is downward.