A couple of commenters expressed concern over the use of centrifugal force after my rant on the use of the word force. So, what is the deal with these two terms? Are they ok to use? Are they real ...

When you buy through links on our articles, Future and its syndication partners may earn a commission. Credit: dwphotos Getty Images Centripetal and centrifugal forces are two terms used to describe ...

TIM PEAKE:Hi I'm Tim Peake. I'm an astronaut based here at the European Space Agency, in Germany. And from December 2015 to June 2016, I spent six months orbiting Earth on the International Space ...

When humanity first started studying motion, circles posed a peculiar puzzle. Why do planets sweep endlessly around the Sun without flying off into the void of space? Why does a stone swung on a ...