A construction worker puts 20J of energy in to one strike of his hammer on the head of a nail. The energy transferred to driving d nail in to d wood is 8J. What is d efficiency of d construction worker's hammering?

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?

Clothes dryer uses about 7 amps of current from a 240 volt line. how much power does it use?

Which lists the fundamental forces in order, from strongest to weakest? strong nuclear, weak nuclear, electromagnetic, gravitational strong nuclear, electromagnetic, weak nuclear, gravitational gravitational, weak nuclear, electromagnetic, strong nuclear electromagnetic, gravitational, strong nuclear, weak nuclear