(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

I had just finished solving 9 energy problems and I'm stuck with this hard question:

A simple pendulum, which consisits of an object suspended by a string. The object is assumed to be a particle. The string, with its top end fixed, has negligible mass and does not stretch. In the absence of air friction, the system oscillates by swinging back and forth in a vertical plane. If the string is 2.00 meters long and makes an initial angle of 30.0 (degrees) with the vertical, calculate the speed of the particle(a) at the lowest point in its trajectory (b) when the angle is 15.0(degrees).

I didn't understand the whole idea of this question ( I mean I can't draw it in my mind)

so plz i'll appreciate any help

thnx

2. Relevant equations

The law of conservation of energy:

M.E.(f) = M.E.(i)

K.E.(f) + P.E.(f) = K.E.(i) + P.E.(i)

K.E.( kinetic enrgy) = 1/2 m(V)^2

P.E.(gravetational potential energy) = mgh or (P.E.=mgy)

I think there is no elastic potential energey

3. The attempt at a solution

I didn't understand the idea of question

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# Homework Help: The coservation of energy principle

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