Can someone help me?
A 73.6 kg base runner begins his slide into second base while moving at a speed of 4.3 m/s. The coefficient of friction between his clothes and Earth is 0.62. He slides so that his speed is zero just as he reaches the base. The acceleration of gravity is 9.81 m/s2 .
a) How much mechanical energy is lost due to friction acting on the runner?
Answer in units of J

Question

Can someone help me?
A 73.6 kg base runner begins his slide into second base while moving at a speed of 4.3 m/s. The coefficient of friction between his clothes and Earth is 0.62. He slides so that his speed is zero just as he reaches the base. The acceleration of gravity is 9.81 m/s2 .
a) How much mechanical energy is lost due to friction acting on the runner?
Answer in units of J

compphysgeek · Answer

the runner has kinetic energy $K_i = 1/2 m v^2$ at the beginning of the slide and it's $K_f = 0$ at the end of the slide. The difference between the final kinetic energy and the initial kinetic energy is the energy lost.

anonymous · Answer

tried that, apparently that formula does not provide the correct answer

anonymous · Answer

although that formula has worked for other people, my utexas hw doesn't accept it

compphysgeek · Answer

i've got approximately 680 J that is lost due to friction, m = 73.6 kg, v = 4.3 m/s. when the runner comes to a stop, his kinetic energy is 0 J, at the beginning of his slide his kinetic energy is 1/2 * 73.6 kg * (4.3 m/s)^2 = 680.432 J. The total energy is lost.

anonymous · Answer

Thanks

compphysgeek · Answer

you're welcome. what was the problem?