Yeah, speed is a killer. A doubling in speed represents a quadrupling of kinetic energy. So, while a 100 kg man-bike moving at 10mph (~16 kph) has (0.51004.444…^2) (0.5mV^2 for kinetic energy, m is mass in kg, V is velocity in m/s) 987 joules of energy, a 100 kg man-bike at 20 mph (0.51008.888…^2) has almost 4000 joules of energy.
Yeah, speed is a killer. A doubling in speed represents a quadrupling of kinetic energy. So, while a 100 kg man-bike moving at 10mph (~16 kph) has (0.51004.444…^2) (0.5mV^2 for kinetic energy, m is mass in kg, V is velocity in m/s) 987 joules of energy, a 100 kg man-bike at 20 mph (0.51008.888…^2) has almost 4000 joules of energy.