The answer is gravity. I hope this helps.
No additional force is required because it's already going downhill
Hi there!
Two possible answers are air resistance and friction.
Friction is caused by the rubbing of the surface of the ground and the surface of the object. Although ice doesn't have much friction, it can still cause friction.
Air resistance is caused by friction between the air and the object. As the object moves along a surface, it collides into many air particles; thus, it slows down.
Hope this helps.
Have an awesome day! :)
Answer: One is called the dependent variable and the other the independent variable. The independent variable is the variable the experimenter changes or controls and is assumed to have a direct effect on the dependent variable.