Answer:
The Elevator
Explanation:
The frame of reference is the immovable item and remains at the same place and can be used for guiding some one. For example I am telling you an address by saying that you will cross the mega store and then there will a Ferrari and on the next street is my home. So you kept searching my home and then you called me again. I checked from my window before receiving call and saw that the ferrari was gone. So it took more time which means that the frame of reference choosen was movable item. The frame of reference choosen is always immovable. So here I want to move towards elevator which is immovable so choosed it. Furthermore, ship is movable item and the ocean doesn't specify right direction thatswhy stars were used in the ancient times.
1- interaction between 2 objects
2- action- reaction force pairs
Answer:
Vx = 35.31 [km/h]
Vy = 18.77 [km/h]
Explanation:
In order to solve this problem, we must decompose the velocity component by means of the angle of 28° using the cosine function of the angle.
![v_{x} = 40*cos(28)\\V_{x} = 35.31 [km/h]](https://tex.z-dn.net/?f=v_%7Bx%7D%20%3D%2040%2Acos%2828%29%5C%5CV_%7Bx%7D%20%3D%2035.31%20%5Bkm%2Fh%5D)
In order to find the vertical component, we must use the sine function of the angle.
![V_{y}=40*sin(28)\\V_{y} = 18.77 [km/h]](https://tex.z-dn.net/?f=V_%7By%7D%3D40%2Asin%2828%29%5C%5CV_%7By%7D%20%3D%2018.77%20%5Bkm%2Fh%5D)
Answer:
a). Maximum Length L=0.929m
b). T=0.83 Hz or 1.2s
c). Longer, the effortless waling T=2.1 Hz or t=0.475s
d). t=1.2s V=0.774 
t=0.475s V=1.95 
Explanation:
Length legs=L=1.1m
angle=50
the step that give the person forms a triangle whose two sides are known and the angle that forms between them, then using trigonometry as the image
Divide the original triangle in two and form a right triangle so the angle is 25 and the L is hypotenuse and the opposite is the step length
a).


Length of the step
L=0.464m*2
L=0.928m
b).
period=T

c).

The period is the inverse of the time of the motion so, the T1 is faster that the T because

d).
The speed is the relation between the distance with time so:
