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Hi guys,
I'm having a bit of difficulty with this concept. So, W=change in KE.
Let's say a hammer strikes a nail into a board. Compared to the moment before the hammer strikes the nail, the mechanical energy of the hammer after its impact will be less because the hammer has done positive work. But, if its KE is decreased from let's say 80J to 20J, wouldn't this mean W=20-80= -60J. How does the calculation yield a negative value if it has done positive work.
I'm having a bit of difficulty with this concept. So, W=change in KE.
Let's say a hammer strikes a nail into a board. Compared to the moment before the hammer strikes the nail, the mechanical energy of the hammer after its impact will be less because the hammer has done positive work. But, if its KE is decreased from let's say 80J to 20J, wouldn't this mean W=20-80= -60J. How does the calculation yield a negative value if it has done positive work.