Question

During an experiment a signal from a spaceship reach the ground station in five minutes. What was the distance of the spaceship from the ground station? The signal Travels at the speed of light that is 3×10 ^ 8 metre per second.

Answer 1

Let s be the distance between the spaceship and the ground station.

Let the speed of signal be u, which is equal to 3 x 10^8 m/s.

The time (t) is 5 min, when converted into seconds, is 300 sec (5 min x 60 sec)

By the 3rd equation of motion…

s = ut + 1/2 (at^2) [here a is acceleration]

Since a is 0, the formula becomes…
​​​​​

s = ut + 0
(Distace = velocity ×time)

s = 3 x 10^8 ×300

s = 9 x 10^10 m or s = 9 x 10^7 km

So, the distance between the spaceship and the ground station is 9 x 10^10 m or 9 x 10^7 Km.