1. A person riding a bicycle on level ground reaches a velocity of 13.4 m/s before stopping. While braking, the internal energy of the brakes, wheels, and road
increase by 5836 J. What is the mass of the cyclist?

To answer this question, you need to recognize that energy is conserved. The initial energy was kinectic and then transferred to internal; therefore, in this problem, (aka final energy) internal energy = kinectic energy (aka initial energy).

Kinectic energy = 0.5 * m * v^2

5836 = 0.5 * m * (13.4)^2
89.78m = 5836
Mass = 65 kgs

That would be the corect answer hope this