F = mass × Acceleration ( give Acceleration is 9.8 )
So force of 5 kg mass on A is
F = 5 × 9.8 = 49N
Force of mass 1 kg on A
F = 1 × 9.8 = 9.8 N
Force of mass 10 kg on A is
F = 10 × 9.8 = 98N
Clearly the 10 kg ball experts the most force cause it has more mass