Your question states: <span>Debbie places two shopping carts in a cart corral. She pushes the first cart, which then pushes a second cart. What force is being exerted?
based by looking at this statement above about Debbie, I understand that she (pushed) Cart (A) first. And then, she exerted (Cart B) next. From the option's that are listed above, I only see two. But from my own words, not from the only (two) options above, I see that (Debbie first exerts the second cart on to the first cart). This reason would be because the first cart is already in the corral. So then she would put the second one in there, this would mean that the second one would push the other one in there. Which means that the velocity would also be in half.
I hope you grabbed my answer in there. ~Jurgen</span>
When Debbie pushes the first cart she is using an applied force. An applied force is created when someone or something pushes another thing using, of course, an applied force. Now, when the second cart is being pushed by the first cart, this is also an applied force. You can tell because the first cart is being pushed using forced and this causes the second cart to be pushed using some of the force that is being transmitted to the first cart. This means the completed sentence should look something like this...
Debbie exerts applied force on the first cart. The first cart exert applied force on the second cart.
It does not violate the law of conservation of energy. The oscillation stops when the energy is lost and the energy is lost because it becomes heat that is created by the air resistance and many other forces found in the surrounding of the oscillating spring.
Gravity is what holds us down on the earth's (or moon's) surface. If you were to weigh yourself on a scale on Earth and then on the moon, the weight read on the moon would be 1/6 your earth weight