Answer:
<em>0.97c</em>
<em></em>
Explanation:
From the relativistic equation for length contraction, we have
= 
where
is the final length of the object
is the original length of the object before contraction
β = 
where v is the speed of the object
c is the speed of light in free space = 3 x 10^8 m/s
The equation can be re-written as
/ = 
For the length to contract to one-fourth of the proper length, then
/ = 1/4
substituting into the equation, we'll have
1/4 =
substituting for β, we'll have
1/4 = 
squaring both side of the equation, we'll have
1/16 = 1 - 
= 1 - 1/16
= 15/16
square root both sides of the equation, we have
v/c = 0.968
v = <em>0.97c</em>
Answer:
Hi there!
The answer is eleven billion years old.
There are 92 natural ones and about 20 more made in particle-Physics labs.
If we only stick to the 92 natural ones, then there are
(92!) / (88! times 4!) = 2,794,155 possible answers to your question.
Here's one: Osmium
Neodymium
Iridium
Gold .
Remaining Distance = 180miles-90miles= 90miles
Time taken for first part of her journey= 90miles / 30miles/h= 3hours
To have average speed of 40mph,
Let the time taken for second part be xh
180 / 3h+xh =40
3+x= 4.5h
x =1.5h
Constant speed she must drive = 90miles / 1.5h = 60mph
