A radar pulse returns 6.0 $\times$ 10^-4s after it was sent out and reflected by an object. What is the separation distance of the radar source and the object?

Question

Quizplus · Accepted Answer

Using the formula: 
distance = speed of light x time / 2

We have: 
time = (6.0 x 10^-4 s) 
speed of light = 3 x 10^8 m/s

distance = (3 x 10^8 m/s) x (6.0 x 10^-4 s) / 2 
distance = 9 x 10^4 m 
distance = 9 x 10^1 km 
distance = 90 km

The correct choice is B, which is 9 x 10^13 meters or 90 km.

A Radar Pulse Returns 6 ×\times× 10-4 s After It Was Sent Out and Reflected by Was

A Radar Pulse Returns 6 $\times$ 10^-4s After It Was Sent Out and Reflected by Was