Answer:
A and B
Explanation:Ap3x approved :)
Answer:
Coefficient of
is more than 4
Explanation:
Oxidation: 
- Balance charge:
......(1)
Reduction: 
- Balance Cr:

- Balance O and H in acidic medium:

- Balance charge:
.......(2)
gives balanced equation:

So coefficient of
is more than 4
It requires a force in the direction opposite to the motion of the object for it to slow down.