A 500-kg ball at the end of a 30-m cable suspended from a crane is used to demolish an old building.

Part A

If the ball has an initial angular displacement of 30? from the vertical, determine its speed at the bottom of the arc.

Express your answer to two significant figures and include the appropriate units.

Velocity will be equal to 8.88 m/sec  

Explanation:

We have given mass m = 500 kg

Length of cable l = 30 m

Angular displacement of the ball

Gravitational potential energy of the ball at the displaced position is equal to

Maximum kinetic energy of the ball

According to energy conservation

So velocity will be equal to 8.88 m/sec

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.