* Gravity is already acting on the elevator. A 1000 kg elevator experiences a downward force due to gravity of approximately 9800 Newtons (1000 kg * 9.8 m/s²).

* To accelerate downward, you need a force *less* than gravity. If you apply a force exactly equal to gravity, the elevator will be in freefall (constant velocity downward). To accelerate downward, you need a force *smaller* than 9800 Newtons.

How to Calculate the Force:

To figure out the exact force needed, you need to know the desired downward acceleration. Here's the formula:

* Force (F) = mass (m) * acceleration (a)

Let's say you want the elevator to accelerate downward at 2 m/s². Here's how to calculate the force:

1. Calculate the force due to gravity: 1000 kg * 9.8 m/s² = 9800 N

2. Calculate the force needed for the desired acceleration: 1000 kg * 2 m/s² = 2000 N

3. Subtract the acceleration force from gravity: 9800 N - 2000 N = 7800 N

Therefore, you would need a force of 7800 N upward (opposing gravity) to achieve a downward acceleration of 2 m/s².

Important Note: The upward force we calculated is actually the net force needed. In reality, this force would be applied by the elevator's cable system to counteract a portion of the gravitational force.