The force required to hold up an object is equal to its weight.

Here's how to calculate it:

* Weight = Mass x Acceleration due to gravity

* Mass (m) = 20 kg

* Acceleration due to gravity (g) = 9.8 m/s² (approximately)

Therefore:

* Weight = 20 kg x 9.8 m/s² = 196 N

So, you would need a force of 196 Newtons to hold up the 20 kg object.