Lesson: Time Dilation Physics

In this lesson, we will learn how to calculate the change in the amount of time between two events as measured in different reference frames.

Lesson Plan

Students will be able to

understand that time passes more slowly for objects moving relative to the observer’s reference frame,
use , the relationship between the time measured by a moving observer and proper time, in all permutations using both SI units and units of ,
understand how to use in combination with calculations of the travel time of light,
understand Minkowski diagrams that show time dilation.

Lesson Worksheet

Q1:

The Minkowski diagram shows two inertial reference frames: frame with axes and and frame with axes and . Frame moves at a speed of relative to frame . The red line shows the world line of a light bulb that is stationary in frame and is initially off. At and , the light bulb flashes for a fraction of a second. In frame , the amount of time between the flashes, , is 10 seconds. How much time passes between the flashes in frame ? Give your answer to one decimal place.

Q2:

A space probe moving away from Earth at a speed of sends out transponder signals back to Earth at regular intervals. On Earth, the signals are received every 153.1 minutes. What is the interval between transponder signals that are sent out in the reference frame of the space probe? Give your answer to one decimal place.

Q3:

A muon has a mean lifetime of s in its rest frame. What is the mean lifetime of a muon, as measured in the reference frame of a laboratory, moving at a speed of relative to the laboratory? Give your answer in scientific notation to two decimal places.