What Is the Speed and Angle of Raindrops in Different Reference Frames?

In summary, the problem involves driving north at a speed of 25 during a rainstorm, where the rain makes an angle of 38 with the vertical. When driving back home at the same speed but in the opposite direction, the rain is falling straight down. To determine the speed of the raindrops relative to the ground and the angle of the raindrops relative to the ground, we can use the equations V=vy+vx and V'=VR-V, where VR is the velocity of the rain. In each reference frame (at rest relative to earth, moving away from home in the car, and moving towards home in the car), the rain will be falling at a different angle.
  • #1
RockenNS42
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0

Homework Statement



While driving north at 25 during a rainstorm you notice that the rain makes an angle of 38 with the vertical. While driving back home moments later at the same speed but in the opposite direction, you see that the rain is falling straight down.
a)From these observations, determine the speed of the raindrops relative to the ground.
b)From these observations, determine the angle of the raindrops relative to the ground.


Homework Equations



V=vy+vx
V'=VR-V

Where VR is the velocity of the rain



The Attempt at a Solution



When driving north I got

V=(-vRsinθR)i + (-vRcosθR)j

Using

V'=VR-V

I get V'=VR-V(-vRsinθR-25)i + (-vRcosθR)j




Im not sure how to set it up for going south. Any suggestions?
Would it look like this? V'=0i+ (-vRcosθR)j
?
And to find θ, would i use [ v'x / v'y}tan-1?


I thinks mostly all the subscripts and whatnot that's messing me up.
Thanks in advance for any help given :)
 
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  • #2
Think of the three reference frames in this problem of interest. At rest relative to earth, moving away from home in the car, moving towards home in the car. In each reference frame the rain will be falling at a different angle. See,



Good luck!
 

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1) What is relative motion and how does it work?

Relative motion refers to the movement of an object in relation to another object. It takes into account the frame of reference, or the point from which the motion is being observed. This means that the same movement can appear different depending on the observer's perspective.

2) How is relative motion different from absolute motion?

Absolute motion refers to the actual, fixed position and movement of an object in space. It is not affected by the observer's perspective. In contrast, relative motion takes into account the perspective of the observer and can change depending on their frame of reference.

3) What is the principle of relativity and how does it relate to relative motion?

The principle of relativity states that the laws of physics are the same for all observers, regardless of their frame of reference. This means that the relative motion between two objects can be described using the same equations and principles, regardless of the observer's perspective.

4) How can relative motion be used in real-life situations?

Relative motion is used in many real-life situations, such as navigation, transportation, and sports. For example, pilots use relative motion to determine their position and speed in relation to other objects, and athletes use it to plan their movements and trajectories in sports like baseball or soccer.

5) What is the difference between relative velocity and relative acceleration?

Relative velocity refers to the change in position of an object in relation to another object, while relative acceleration refers to the change in velocity of an object in relation to another object. Essentially, relative velocity describes the speed and direction of an object's movement, while relative acceleration describes how that speed and direction are changing over time.

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