Question

A unit of time sometimes used in microscopic physics is the "shake". One shake equals 10−8 s.

(a) How many more shakes in a second are there than seconds in a year?
(b) Humans have existed for about 106 years, whereas the universe is about 1010 years old. If the age of the universe is taken to be 1 "universe day", for how many "universe seconds" have humans existed? "universe seconds"

Answer 1

(a) There are 3.17 times more shakes in a second than seconds in a year.

(b) Humans have existed for 9067.72 universe seconds.

Step-by-step explanation:

(a) First we calcule how many seconds are in a year. One year have 365 days, one day has 24 hours, one hour has 60 minutes and one minute has 60 seconds, so:

`60s*60*24*365=3.1536*10^7s`

Now, we calculate how many shakes are in a second:

`1s*(1shake)/(10^(-8)s)=10^8shakes`

Finally, we calculate how many more shakes in a second are there than seconds in a year:

`(10^8s)/(3.1536*10^7s)=3.17`

(b) Using a simple rule of three we can calculate how many "universe seconds" have humans existed, recall that 1 day has 86400 seconds:

1010 years--------->86400s

106 years----------> x seconds

`x=(106y*86400s)/(1010y)=9067.72s`