A force over distance is work the unite is joules
I think the answer is A because it is gravity that caused the planets to form and start orbiting around the nearest star which is the sun
The answers false I believe
You can use mostly anything as long as it is circular. Depending on how big it is, you could use sturdy paper plates and use a stick/rod and tape to hold it together, or you could use bottle caps if the car you are trying to make is really small.