Homework Help

A 35kg kids climb to the top of a 4.5m ladder of slide. While sliding down student...

user profile pic

andrewmezzo | Student, College Freshman | (Level 1) Valedictorian

Posted December 9, 2012 at 9:46 PM via web

dislike 1 like

A 35kg kids climb to the top of a 4.5m ladder of slide. While sliding down student reaches 3.3m/s at the bottom of the slide. How much work is done?

Work done  by friction

1 Answer | Add Yours

Top Answer

user profile pic

jeew-m | College Teacher | (Level 1) Educator Emeritus

Posted December 10, 2012 at 6:58 AM (Answer #1)

dislike 1 like

At the top of the ladder the kid has the potential energy. Once he slides down this energy will be converted to kinetic energy and energy to work against friction.

Using the law of conservation of energy;

Potential energy = Kinetic energy+work done against friction

`mgh = 1/2m*v^2+F*S`

`35*9.81*4.5 = 1/2*35*3.3^2+F*4.5`

`F = 301J`

 

So the work done is 301 J and this work is done against friction.

Sources:

Join to answer this question

Join a community of thousands of dedicated teachers and students.

Join eNotes