In the case of block and tacklle arrangement mechanical advantage increases with the number of pulleys. Why?

When you drop a pebble from height a it reaches the ground with speed v if there is no air resistance. from what height should you drop it so it will reach the ground with three times the speed? (a) 9m (b) 3m (c) 6m (d) 18m

In physics the desire of an object to keep doing what it is doing is termed?

The image below shows numerous volcanic mountains in the pacific northwest. what is the most likely cause of the volcanic and earthquake activity in this region?