# Ch 23-1 Quiz

## Ch 23-1 Quiz

1. In "Relativity Country" the conductor in a train traveling with 13.13 x107 km/hr aims the beam of a flashlight in the direction of the train motion. What is the speed of the light beam relative to ground in m/s (sheet 3)? Indicate with a positive (negative) sign whether the result would be different (the same) if the flashlight would be pointed in the opposite direction.
= 3E8 (negative)

User X
Guest

## # 2

2. A particle travels with 16.92 % of the speed of light past you. It has a clock attached to it which is identical to the clock you carry. You choose to ignore Special Relativity and claim the 2 clocks will show the same time. What is the magnitude of the percentage error you make (sheet 5 top,6. Give the magnitude of the difference of the relativistic factor from 1.00, multiplied by 100 ) ? Indicate with a positive (negative) sign whether the percentage error decreases (increases) with increasing speed of the particle.
=still working on # 2

User X
Guest

## # 3

3. A radioactive particle has a lifetime of 1.3 x10-8 s before it decays (dies) after its creation when observed at rest. The particle has a velocity of 2.674 x108 m/s relative to you standing in the laboratory. What is the lifetime of the particle as measured by you (sheet 6, ? Indicate with a positive (negative) sign whether the liftime measured by you when "riding on the particle" is smaller (larger) than your result.

User X
Guest

## # 4

4. The lifetime of a hypothetical radioactive particle passing you with a speed of 0.9974 c, where c is the speed of light, is determined by you to be 4.933 x10-5 seconds. What is the "proper" lifetime of the particle (the time measured when it is at rest with respect to the observer) (sheet 6,9) ? Indicate with a positive (negative) sign whether the "proper lifetime" is (not) the one you measure when "riding on the particle".
=4.933E-5 * (sqrt(1-(.9974)^2) (answer is positive)

User X
Guest

## # 2

if anyone can help with # 2....
i cant seem to figure out what i'm doing wrong on that one

User X
Guest

## Question #2

100*(1-(sqrt(1-((value provided/100)^2))))

Thank you, User X, for the remainder of the problems.

helping
Guest

## #3

I keep getting a non-real answer for #3! how do u do it to get a real answer????

blah
Guest

## Question 3

You're getting a non-real answer because you're not using parentheses correctly.
(1.3E-/(sqrt(1-[(...E8)/(3E8)]^2)))

Now regardless of doing this, I'm still getting a wrong answer. Though, you do get a "real" answer

Can someone please comment on this....
thanks

guest222
Guest

## #3

Hey....i'm not sure exactly what your doing wrong but the answer above that User X posted does work...

phyfrk
Guest

## #3

i think you might need to just check your parenthesis
other than that i think your work itself might be fine
and try to double check your numbers, maybe you entered something wrong on your calc?

phyfrk
Guest

## #3

your best bet for #3 is to do the equation in parts..thats the only way it worked for me..putting the whole thing into ur calculator is most likely gonna give u the wrong answer bc theres too much room for error..so try that

guest_01
Guest

## 3

I cantttttttttttt get 3 at all

i have error i tried to break them down but same thing

3
Guest

## #3 sucksssss

help! still cannot get it right! what was ur numerical answer for #3? i've tried so many times!
A radioactive particle has a lifetime of 3.603 x10-8 s before it decays (dies) after its creation when observed at rest. The particle has a velocity of 2.734 x108 m/s relative to you standing in the laboratory. What is the lifetime of the particle as measured by you (sheet 6, ? Indicate with a positive (negative) sign whether the liftime measured by you when "riding on the particle" is smaller (larger) than your result.

k8
Guest

## Re: Ch 23-1 Quiz

the only way you get a nonreal number is if you used the first number in placement of the second number

in respo
Guest