The correct answer is Model A shows the three-dimensional shape of the molecule, but Model B does not.
Explanation:
Model A and B show the structure of a molecule. In the case of model A, the structure is represented through the use of three-dimensional shapes, while in model B the structure is represented using the letters of each element and showing how each element is connected to others.
In this context, one feature that makes model A better is that this represents the molecule using a 3D model, which is better to understand how the molecule looks like and what is its structure. Moreover, both models are alike because they show the number of atoms of each element, although model A does not show the types of elements.
Potential energy is high and kinetic is equal i believe.
Answer:
The surface gravity is inversely proportional to the square of the radius of the planet
Explanation:
The gravity at the surface of a planet is given by:

where
G is the gravitational constant
M is the mass of the planet
R is the radius of the planet
We see from the formula that the surface gravity is inversely proportional to the square of the radius of the planet, R.
At the Earth's surface, the value of the surface gravity is approximately 9.81 m/s^2.
I attached the missing picture.
Let's analyze the situation as spring goes from stretched to unstretched state.
When you stretch the string you have to use force against ( you are doing work) this energy is then stored in the spring in the form of potential energy. When we release the spring the energy is being used to push the two carts. When the spring reaches its unstretched length its whole initial potential energy has been used on the carts, and this is the moment when two carts have maximum velocity.
The potential energy of compressed ( stretched) spring is:

The kinetic energy of two carts is:

So we have:

Momentum also has to be conserved:

Momentum before the release of the spring is zero so it has to stay zero. We plug this back into the expresion we got from law of conservation of energy and we get:

Now we go back to the momentum equation: