Al is moving by you at a very high speed (close to the speed of light).You get out a clock and measure 10 seconds going by.If you also watch a clock in Al's ship,how much time will you see it record during your 10 seconds?
A)Al's clock will record less than 10 seconds.
B)Al's clock will record more than 10 seconds.
C)Al's clock will agree that 10 seconds go by.

Question

Quizplus · Accepted Answer

This scenario involves time dilation, a prediction of Einstein's theory of relativity. When an object is moving at high speeds, time appears to pass slower for that object relative to a stationary observer. From your perspective, you witness 10 seconds go by on your clock. However, since Al is moving at a high speed relative to you, time appears to pass slower for him. Therefore, Al's clock will record less than 10 seconds during your 10 seconds. This effect becomes more significant the closer Al's velocity is to the speed of light.

Al Is Moving by You at a Very High Speed