Question

Class I lever can have M.A. = 1, M.A. < 1 and M.A. > 1. Explain each giving examples.

Answer 1

E.g. of class I lever with M.A. = 1:  A physical balance has both arms equal (i.e. effort arm = load arm), thus its M.A. = 1 
E.g. of class I lever with M.A. = 1: A pair of scissors used to cut a piece of cloth has blades longer than the handle (i.e. effort arm is shorter than the load arm), thus its M.A. = 1.
E.g. of class I lever with M.A. = 1: Shears used for cutting thin metal sheets have much longer handles as compared to the blades (i.e. effort arm is longer than the load arm), thus its M.A. = 1 and it serves as a force multiplier.