Question

QUESTION 4

1. The evil villain Science Hater is flying towards our hero Super Physics Dude at a speed of 0.832 c. Science Hater carries a powerful laser which he turns on and points the beam of light directly at Super Physics Dude. Given his interest in physics, Super Physics Dude decides to measure the speed of the light coming towards him from Science Hater's laser. What speed does he measure?

		1.832 c
		c
		0.832 c
		0.168 c

QUESTION 5

1. Which is the proper reference frame?

		The frame of reference at rest relative to the "important stuff" of the problem.
		The frame of reference moving relative to the "important stuff" of the problem.
		The frame of reference in which proper etiquette is always observed.
		The frame of reference in which everyone has impeccable manners.

QUESTION 6

1. The famous Michelson-Morley experiments showed what results and were performed where?

		They showed that the speed of light does depend on the relative velocity between the source of light and the observer. They were performed at CERN, the famous particle accelerator lab.
		They showed that the speed of light does not depend on the relative velocity between the source of light and the observer. They were performed at CERN, the famous particle accelerator lab.
		They showed that the speed of light does depend on the relative velocity between the source of light and the observer. They were performed in Cleveland, Ohio.
		They showed that the speed of light does not depend on the relative velocity between the source of light and the observer. They were performed in Cleveland, Ohio.

Answer 1

Answer to Question 4) is,

The speed of light c is an universal constant.

The speed of light c does not depend on the relative velocity between source and observer.

That is both Science hater and super Physics dude both will observe the same speed of laser light.

lets look at this mathematically,

Here we have,

relative velocity of science hater with respect to super physics dude,

velocity of light relative to science hater =

we will use relativistic formula of velocity addition to find the velocity of laser light   relative to super physics dude,

so the velocity of light measured by physics dude  .

Answer to question 5) is,

The frame of reference at rest relative to "important stuff" of the problem.

Most of the times the "Important stuff" of a problem involves proving relations between physical quantities or finding values of variables and constants in a "particular frame", so we must choose frame at rest relative to that particular frame to answer the questions. take above question and answer for example.

If the the problem involves finding the conserved quantities ( that is quantities whose values are independent of the frame of reference) then it does not matter which frame of reference we choose. at such times its better to choose the frame which  makes the calculations easy.

Answer to question 6) is,

They showed that the speed of light does not depend on the relative velocity between the source of light and the observer. They were performed in Cleveland, Ohio.