A friend hands you two springs with different spring constants. Without using any measuring tools, explain how you could decide which spring has a bigger spring constant. Use your results to predict the force the spring will exert when it is stretched to 15 cm. Show your work or explain your reasoning.

A friend hands you two springs with different spring constants. Without using any measuring tools, explain how you could decide which spring has a bigger spring constant. Use your results to predict the force the spring will exert when it is stretched to 15 cm. Show your work or explain your reasoning.