A radar pulse returns from a stationary object 48 μs48\ \mu\mathrm{s}48 μs after transmission. The pulse speed is 3.0 × 108 m/s. What is the distance to the object?
14.4 km14.4\ \mathrm{km}14.4 km
3.6 km3.6\ \mathrm{km}3.6 km
7.2 km7.2\ \mathrm{km}7.2 km
72 km72\ \mathrm{km}72 km