180

Step 1: Start with the given velocity of the body:
$$ v = 50 \, ms^{-1} $$
Step 2: Convert meters per second to kilometers per hour. To do this, we use the conversion factors:
1 meter = 0.001 kilometers
1 second = \frac{1}{3600} hours
Therefore, the conversion is:
$$ 50 \, ms^{-1} = 50 \times \frac{0.001 \, km}{1 \, m} \times \frac{3600 \, s}{1 \, h} $$
Step 3: Calculating the numerical value:
$$ = 50 \times 0.001 \times 3600 = 180 \, km/h $$
Step 4: The final numerical value of the velocity in kilometers per hour is 180.
Therefore, the answer is 180.