Which FBD is INCORRECT based on the gif

.) the observation by semmelweis that more mothers died of childbed fever when their doctors also worked in the morgue

there are no contact forces mentioned on the list of choices that you've provided.

blue light is scattered in different directions by the tiny molecules of air. blue is scattered more than other colours because it has a shorter distance to travel which results in smaller waves. this is why we see a blue sky most of the time.

b. false

explanation:

suppose a rock in free fall is dropped off a cliff. after falling for 5 seconds, its speed would not be 100 m/s.