Sea water conducts electricity. Which statements gives the best explanation for this?
Can you tell me why this is an answer?
"The sea water contains ions that have positive charges and ions that have negative charges."
Why specifically "positive" and "negative" explain why it conducts.
A weightlifter raises a bar of mass 50KG until it is above his head - a total height gain of 2.2m.
How much gravitational potential energy has it gained?
I know that GPE is equal to the weight (N) * Height difference so this = 1100J
How much work must he do to hold it there for 5 seconds?
How...