Why do wrecking balls amplify damage done?

[tahayassen]

Homework Statement

A wrecking ball is commonly used to destroy old buildings. The energy comes from a motor pulling a large pendulum back, which then allows it to swing against a wall. Why not just use the motor to do the same work on the wall?

2. The attempt at a solution

The kinetic energy AND the gravitational potential energy is used to break the wall with a pendulum whereas a motor will only have kinetic energy.

 

[Spinnor]

For small buildings direct mechanical action is used, see,

http://www.youtube.com/watch?v=I9FP7Y2Ig1Y&feature=related

For large and stronger structures use the ball or explosives, see,

http://www.youtube.com/watch?v=SJkdYuzViqo&feature=related

Calculate the peak force generated when a 1 ton ball moving at 15 ft per second stops within 1 inch. If I did it right I get about 90,000 lbs. force concentrated over a relatively small area. It would be difficult to apply such a force many stories up with machines we have.

 

[tahayassen]

For small buildings direct mechanical action is used, see,

http://www.youtube.com/watch?v=I9FP7Y2Ig1Y&feature=related

For large and stronger structures use the ball or explosives, see,

http://www.youtube.com/watch?v=SJkdYuzViqo&feature=related

Calculate the peak force generated when a 1 ton ball moving at 15 ft per second stops within 1 inch. If I did it right I get about 90,000 lbs. force concentrated over a relatively small area. It would be difficult to apply such a force many stories up with machines we have.

I thought force is mass times acceleration - not mass times speed.

edit: Never mind. I get it now. Thanks.