Well, basically because the observations can help you out during the experiment.
Answer:
a = 2.77 [m/s²]
Explanation:
To solve this problem we must use the following equation of kinematics.

where:
Vf = final velocity = 19 [m/s]
Vo = initial velocity = 44 [m/s]
a = acceleration [m/s²]
t = time = 9 [s]
Note: The negative sign in the above equation means that the train is decreasing its velocity.
19 = 44 - a*9
9*a = 44 -19
a = 2.77 [m/s²]
Answer:
n order to walk across the floor, you push backwards on the floor with your foot. Newton's Third Law says that the reaction force to this action force is "floor pushes you forward" (Action: You push floor backwards. Reaction: floor pushes you forward.) So, when you walk, it is the floor that pushes you along!
Explanation:
Feathers sharp ,teeth some of them , wings ,backbones