# physics

posted by
**jennifer** on
.

The length of a simple pendulum is 0.82 m and the mass of the particle (the "bob") at the end of the cable is 0.69 kg. The pendulum is pulled away from its equilibrium position by an angle of 6.7 ° and released from rest. Assume that friction can be neglected and that the resulting oscillatory motion is simple harmonic motion. (a) What is the angular frequency of the motion? (b) Using the position of the bob at its lowest point as the reference level, determine the total mechanical energy of the pendulum as it swings back and forth. (c) What is the bob's speed as it passes through the lowest point of the swing?

I will be happy to critique your thinking or work on this. Angular freq comes as a standard formula, and the other items for energy concepts (PEmax= KEmax)

i know for part a the answer is 3.547

rad/s but i don't know how to do part b & c

please someone tell me how to do part b & c i know how to do part a only

From geometry, figure how high from the base is the bob when it starts. Its potential energy is mgh where h is the vertical height. At thebottom, the KE has to equal that starting energy.

1/2 mv^=mgh

you can calculate the velocity.

but how do you do part b i still don't get it

thanks for the help