Question

speed of light is 3×10^8m/sec. the circumference equador is 4×10^4km. if light turns around equador for 5 min, how many tours can we count?​

Answer 1

Answer: 2250 tours

Step-by-step explanation:

We have the following data:

Speed of light:
`c=3(10)^(8)m/s`

Circumference of the equador:
`r=4(10)^(4)km (1000 m)/(1 km)=4(10)^(7)m`

The time in which light turns around equator:
`t=5 min (60 s)/(1 min)=300 s`

We need to find how many tours does light do around the equator in
`t=300 s`

Let's begin by the expression of the speed, which is a relation between the traveled distance (
`d`) and time:

`c=(d)/(t)` (1)

Isolating
`d`:

`d=c.t` (2)

`d=(3(10)^(8)m/s)(300 s)` (3)

`d=9(10)^(10)m` (4) This is the distance light travels in 5 min.

Now we need to know to how many tours is this distance equivalent, we can know this by a Rule of three:

1 tour ----
`r` (circumference of the equator)

? tour ----
`d`

Then:

`?=((1 tour)(d))/(r)`

`?=((1 tour)(9(10)^(10)m))/(4(10)^(7)m)`

`?=2250 tours` This is the count of tours in 5 minutes.