A200-kg boulder has 39,200 joules of gravitational potential energy. what height is it at?

Why is alternating current more effective at long–distance travel than direct current? a. the power lines are made out of conductors. b. transformers increase or decrease voltage as needed. c. the ac generator is more efficient. d. ac has lower voltage than dc.

Crowbar of 5 metre is used to lift an object of 800 metre if the effort arm is 200cm calculate the force applied

This is the substance(s) formed in a chemical reaction.