Given the task definition, example input & output, solve the new input case.
In this task, you need to write a topic word from the given fact. The topic word must have at least one word overlap with the given fact. The topic word often involves adding a new word from a related concept. In your topic word, use at least one word from the given fact. Topic words with two or more words work best.
Example: Fact: pesticides cause pollution.
Output: pollution harms.
This is a good topic word, because it contains one overlapping word "pollution".

New input case for you: Fact: force causes the speed of an object to increase.
Output:
force motion.