It has mass and takes up space is correct.
Friction <span>is most responsible for slowing a bicycle down when the brakes are applied</span>
The answer would be 200000 J. the equation for kinetic energy is 1/2 mass times velocity squared. 1/2 of 1,000 is 500. and 20*20 is 400. So, multiply 400 by 500, and that gives you your answer,