A 75kg skater starts his skate at 4m above ground, the horizontal distance to th

Question

A 75kg skater starts his skate at 4m above ground, the horizontal distance to the bottom of the track is 6m. The ground = 0 gravitational potential energy. Coefficient friction of the track =0. The horizontal surface does have friction.

Why does the skater stop during the run on the horizontal surface?

Calculate the speed of the skater at the bottom of the track? (show all work)

What force is responsible for making the skater stop?

Calculate the work done by force of friction on the horizontal surface using the Work Kinetic Energy Theorem? (show all work)

Using the definition of work, determine the coefficient of friction along the horizontal surface.

Show all work and calculations.

Explanation / Answer

he stops because there is frictional force acting on the skater from tje ground so it is loosing enrgy and finaly his TE becomes zerfo

conserving enrgy

gain inKE= loss in PE

thue 1/2*mV^2=mg

or v= root 2gh

=root 2*9.8*4

8.85 m/s

applying enrgy conservation on the horizontal track we get

work done by friction = loss in KE

so work done by friction = - 0.5*m*v^2

= - 2940 J

work = F*d

thus F= -umg

d is distnce moved on track

sp -u*75*9.8*6= -2940

thus u= 2/3

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