What are some different kinds of bias and how can they ruin a research project

Three types of bias can be distinguished: information bias, selection bias, and confounding. These three types of bias and their potential solutions are discussed using various examples.

Bias can damage research, if the researcher chooses to allow his bias to distort the measurements and observations or their interpretation. When faculty are biased about individual students in their courses, they may grade some students more or less favorably than others, which is not fair to any of the students.

Explanation:

             I'm not sure about the different types (I think one was selective bias) but they can ruin research if the person decides to use there bias.                                                       Example: if I'm trying to prove such and such movie is good and I'm doing research on it. I might choose to do a poll. Because I want to prove that this movie is the best I will pick the people who I know liked the movie. That is being biased.

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.