Practice Problem about the Energy of a Pendulum

[stephy]

Homework Statement

A small sphere of mass m is fastened to a weightless string of length 0.5m to form a pendulum. The pendulum is swinging so as to make a maximum angle of 60 degrees with the vertical.
a) What is the velocity of the sphere when it passes through the vertical position?
b) What is the instantaneous acceleration when the pendulum is at its maximum deflection?

Relevant Equations

a) v=sqrt(L*g*sine(thet)*tan(thet)
b) ac= v^2/r

Answer:
a) 7.35 m/s
b) 216.09 m/s^2

*Is this correct?

 

[Orodruin]

It would be easier to offer you help if you offer a bit more detail for your reasoning.

In both of the cases a) and b), what is your argumentation behind the expressions?

 

[phinds]

*Is this correct?

I suggest you read the forum rules, one of which is that you are required to show work (not just answers).

 

[rsk]

No working out offered by me (yet), but I would look at energy considerations for the first part.