This is not a lesson in physics, but a conversion formula developed by Marketing Experiments. Translation:

C = Probability of conversion
m = Motivation of user (when)
v = Clarity of the value proposition (why)
i = Incentive to take action
f = Friction elements of process
a = Anxiety about entering information

Summary: The probability of conversion depends on the match between the offer and visitor motivation + the clarity of the value proposition + (incentives to take action now-friction)-anxiety. The numbers next to each character signify the importance of them.

How to apply this to your copy:

• Is your value proposition easy to understand and perfectly clear? Would everyone understand what you offer and how it's beneficial to them?
• Go through your copy and see if there's any way to make your statements clearer.
• Communicate value: don't just list features, turn them into benefits.
• Make a list of all possible questions, doubts and objections that prospects might have in the buying process. Address them.
• Make the buying or signup process as easy as possible, remove everything that is not absolutely necessary.
• Add microcopy: explain why you need certain data and what happens after they give it to you.
• Provide full information: what happens after they buy, what can they expect, when is the product shipped, what's the delivery time.
• Add risk reversal: what kind of guarantees are in place? What happens if they don't like it, or it's not what they thought, etc?