Answer the following: a. explain how a pulley changes the amount of force needed to lift an object. b. do all pulleys change the amount of force needed to move an object? justify your answer.

If you want to lift something that weighs 100kg, you have to pull down with a force equivalent to 100kg, which is 1000N (newtons). I hope this helps, please mark brainiest if it does. I will attach a picture I found off the internet to further help you  :)
(There are like 1,000,000,000,000,000,000,000 other ways I could have put that, to make it sound less creepy, I could just edit it now instead of writing this huge thing... oh well lol)