A thin rod, of length L = 2.0 m, with negligible mass, can pivot about one end to rotate in a vertical circle. A ball of mass m = 5.0 kg is attached to the other end. The rod is pulled aside to an angle of ϴ0 = 30.0° and released with zero initial velocity. What is the speed of the ball at the lowest point?
Thanks guys

Question

A thin rod, of length L = 2.0 m, with negligible mass, can pivot about one end to rotate in a vertical circle. A ball of mass m = 5.0 kg is attached to the other end. The rod is pulled aside to an angle of ϴ0 = 30.0° and released with zero initial velocity. What is the speed of the ball at the lowest point?
Thanks guys

anonymous · Answer

can the motion be considered to be as of a simple harmonic one..i mean that holds good for small angles...

anonymous · Answer

@ZeHanz

anonymous · Answer

Yes I believe so.

anonymous · Answer

sorry i can't solve this:/ and if i did, i think i would give u the wrong answer,. maybe @ZeHanz  or @mathaddict4471 @mathstudent55  can help.

anonymous · Answer

so now we get the amplitude from the initial condition given as also we know the angular frequency ..and the Aw(a-amplitude.w-angular frequency) corresponds to the max velocity which occurs at the mean position...

anonymous · Answer

Unfortunately I have no idea what any of that means, so it must not be the way that I am supposed to solve it.... Any other ideas?
I'm assuming it has to do with the angular kinematic equations.

zehanz · Answer

@seiga: sorry, I don't know much about pendulums...

anonymous · Answer

well obviously that's a perfect method too..see since the only force doing work on the rod is gravity which is again a conservative force..so we can conserve the total mechanical energy ..now the gravitational force can be assumed to be acting through the centre of mass of the rod..so plug that in and write down the total mechanical energy for both the states and solve for the variable v