Tarnish is produced by a redox reaction that occurs when a metal reacts with a nonmetallic compound. The green tarnish on a copper penny might be
produced by a reaction between copper and hydrogen sulfide. What occurs
during this reaction?
A. Hydrogen sulfide acts as an acid, and copper acts as a base.
O B. A double-replacement reaction takes place.
C. Copper atoms gain electrons from sulfur atoms.
D. Copper atoms lose electrons to sulfur atoms.

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

What is the most useful equation for electric power?

3. a worker pushes a 30.5 kg polished stone along a polished table with a force on bonin a straight line for 5.20 s after starting from rest. there is no friction between thestone and the table. at the end of the table. the stone is hooked to a cable with a lengthof 62.0 cm to rotate it to a rough table to store until they can be picked up. the roughtable has a coefficient of static friction 0.702 with the polished stone. remember that 8= 9.80 m/s2a) what is the speed of the stone when it is hooked to the cable? b) what is the tension in the cable while the stone is rotating? (there is still nofriction)c) how much force is needed to make the stone begin sliding from rest on therough table? ius = 0.70262.0 cm30.5 kg20.5 kg6= 0