Which scientist said as velocity increases time slows?

Answer 1

Einstein's theory (or one of them anyway) said that as velocity increases, time slows. However, as the velocity increases of any object (except light) its mass increases. (just thought that extra info might be needed) hope that helps! : )

Answer 2

This concept is known as time dilation and is a principle of Albert Einstein's theory of relativity. It suggests that time appears to pass more slowly for an object in motion relative to a stationary observer.