A 70.0 kg base runner moving at a speed of 4.0 m/s begins his slide into second base. The coefficient of friction between his clothes and Earth is 0.70. His slide lowers his speed to zero just as he reaches the base. How much mechanical energy is lost because of friction acting on the runner? A. 1100 J B. 560 J C. 140 J D. 0J 8. How far does the runner slide? F. 0.29 m G. 0.57 m H. 0.86 m J. 1.2 m

B. 560 J

J. 1.2 m

Explanation:

v = Final velocity = 0

u = Initial velocity = 4 m/s

= Coefficient of friction = 0.7

m = Mass of runner = 70 kg

g = Acceleration due to gravity =

Kinetic energy is given by

The mechanical energy lost is 560 J

Acceleration is given by

From kinematic equations we get

The runner slides for 1.2 m

pythagoras' theorem

square root (-5^2+9^2)

square root (25+81)

square root (106)

angle is tan^-1(9/5)

neg x, pos y