Kinetic energy and potential energy, Physics

Assumptions: Kinetic Energy=KE, Potential Energy=PE

m=mass of the skateboarder=55 kg, Velocity v=1.80m/s

So ,Initial Energy(KE) of the skateboarder=mv2/2 = 0.5* 55 * (1.8)^2 = 89.1 J

Now from law of conservation of energy we can write that

Work Done by the man/boy

=(Change in KE)+(Change in PE)+(Friction)

            =(KE final-KE initial)+(PE final- PE initial)+(Friction)

            = (KE final-KE initial)+ ?PE +(Friction)---------------------(1)                                                                                     

Now (PE final-PE initial) is to be determined.

But PE initial=0

So (PE final- PE initial)=?PE=PE final

And KE final= mv2/2=.5*55*(6)^2=990 J

KE initial=89.1 J(already determined)

So (KE final-KE initial)= 900.9 J

Work done by the man=80 J, Friction=-265 J

Now from equation (1) we get

80=900.9+?PE-265

?PE=-1085.9 J

        =-1.09KJ(approx)

This -ve sign indicates that the skateboarder losses some vertical height.

Part 2:

Change in potential energy

=?PE

=m*g*h(m=mass, g=gravitational force, h=height)

So -1.09KJ=55*9.8*h

    h= -1085.9/(55*9.8)

      =-2.02m or 2.02 m below the starting point

Posted Date: 3/20/2013 1:10:45 AM | Location : United States







Related Discussions:- Kinetic energy and potential energy, Assignment Help, Ask Question on Kinetic energy and potential energy, Get Answer, Expert's Help, Kinetic energy and potential energy Discussions

Write discussion on Kinetic energy and potential energy
Your posts are moderated
Related Questions
‘q' is a path function. Under what situations it will be a state function? Define and illustrate heterogeneous and homogenous systems with examples.

ISOLATED SYSTEM: "When a number of bodies are like that they can exert force upon one another and no external agency exerts a force on them, they are said to form an isolated s

What is Faraday's law of electromagnetic induction? Determine its differential form.

what is the force?

what is quantum gravity


what is the formula of work done

Need a word that descripes relationship of parabolic function? Thanks!

Which of the subsequent conditions must be met in order for a uniform magnetic field to exert a force on a particle? Ans: A charged particle has to be in a magnetic ground

Discuss about the Single-mode fibre in short. Single-mode fibre: A single-mode fibre consists of a narrow core (8 to 10µm) and refractive index in between the core and cladd