A force of 6 N is applied starting at 10 seconds, at 15 seconds?

Well depending on what every is pushing it with the force of (n) newtons its will stay at the same force rate but velocity and speed will change.

mass and volume are the answers you are looking for

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.