To convert 280 km/hr to m/sec, you can use the following conversion factor:
1 km/hr = 0.2778 m/sec
So, to convert 280 km/hr to m/sec, you can multiply it by the conversion factor:
280 km/hr * 0.2778 m/sec = 77.784 m/sec (rounded to three decimal places)
Therefore, 280 km/hr is approximately equal to 77.784 m/sec.