Mass of the dart = 0.01 kg
Speed at which the dart is thrown = 20 m/s
Kinetic Energy = (1/2) * mass * speed * speed
= (1/2) * (0.01) * (20) * (20) Joules
= (400 *0.01)/2 Joules
= 4/2 Joules
= 2 Joules
So the kinetic energy of the dart is 2 Joules. I hope this is the correct answer and it has helped you.