The force exerted by the cup on your foot is greater than the weight of the cup.
This is because the cup is accelerating downwards due to gravity, and this acceleration will cause an additional force to be exerted on your foot.
Here is a free-body diagram of the cup:
mg
|
v
|
----------
| |
F mg
---------
Where:
mg is the weight of the cup
v is the velocity of the cup
F is the force exerted by the cup on your foot
As you can see, the force exerted by the cup on your foot is the sum of the weight of the cup and the force due to acceleration. Since the acceleration is downwards, the force due to acceleration will also be downwards.
Therefore, the total force exerted by the cup on your foot will be greater than the weight of the cup.
When the cup lands on your foot, it will come to a sudden stop. This means that the cup will exert a large force on your foot in a short amount of time.
This force is greater than the weight of the cup because it is the force that causes the cup to stop moving.