In which way of the following situations would a spring scale be used?

a) a study of the effect of different fertilizers on plant growth

b) an investigation of the efficiency of different simple machines

c) a measurement of the effect of a catalyst in a chemical reaction

d) a comparison of the patterns of light created by a different prisms

The correct answer is (B): a spring scale can be used in an investigation of the efficiency of different simple machines A spring scale is used to measure weight (force) of a load. When determining efficiency of a machine, we must know energy used to perform a certain work or activity and for us to do that we have to know the amount of effort or energy required or used in that situation, since, a spring balance can measure weight (force), then it can be very handy in the process of measuring the efficiency of a simple machine. The other choices (A),(C), and (D), in those situations, the spring balance cannot be of any use.

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.