How can you use a model to explain how people see

Which of the following explains why it took so long for the public to accept the negative health effects of smoking? a)people were waiting for counter reasons, and those were presented. b)scientists had not completely finalized their results, which took 30 years. c)cigarettes were cheaply available and media channels were very inefficient. d)cigarette manufacturers were trying hard to bring an alternative into the market

Amira pulls a 3 pound wagon 4 feet. how much work has she done?

What is the force that opposes motion and works against the downward pull? a) friction b) gravity c) weight d) acceleration