Answer:
3 hours
Explanation:
180 divided by 60 (mph means miles per hours by the way)
A and c...............................
Explanation:
It is given that,
Length of the helicopter, l = 3.1 m
The helicopter rotates, the length of helicopter will become the radius of circular path, r = 3.1 m
Angular speed of the helicopter, 
(a) The centripetal acceleration in terms of angular velocity is given by :



(b) Let v is the linear speed of the tip. The relation between the linear and angular speed is given by :


v = 90.89 m/s

Hence, this is the required solution.
Answer:
So when you are riding in a car everything you see is from the cars frame. Where if you are standing by the highway it is from your point of view.
Explanation:
So lets say someone sees a apple core outside the bus it looks like the apple is traveling the opposite way of the bus but to the man standing by the highway would say it is stationary.
Usually, Scientists use "Parallax Method" in order to determine the different positions of an object
Hope this helps!