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## Main Question or Discussion Point

In my physics textbook chapter of work 3 statements are made which I am having trouble sorting through.

1. When W>0 the system's energy increases, when W<0 the system's energy decreases.

2.

3.

Here is where my confusion begins. If I move a 1kg brick from 0m to 1m I have added potential energy, more energy is stored in the system. Statement 2 asserts that because

I am missing something. Please help.

1. When W>0 the system's energy increases, when W<0 the system's energy decreases.

2.

**ΔE**=**ΔK+****ΔU+****ΔTherm = W**3.

**ΔU = -W**

Here is where my confusion begins. If I move a 1kg brick from 0m to 1m I have added potential energy, more energy is stored in the system. Statement 2 asserts that because

**ΔU**increases,**ΔE**will also increase and work will be positive. Statement 1 says that W>0 so the system's energy increases. But statement 3 says that**ΔU= -W**, but we can see clearly that**ΔU**was positive and that work is also positive.I am missing something. Please help.