Kinematics of moving car and falling rain

In summary, the man driving his car at a velocity of 25m/s sees rain falling at an angle of 30 degrees when looking through his side windows. However, when he stops, he realizes that the rain is actually falling straight down at 0 degrees. The velocity of the rain, relative to the car, is calculated to be 50m/s when the car is moving and 43.301m/s when the car is stopped. However, switching the sin and cos values in the calculations results in the textbook's answer of 25m/s for the stopped car and 28.86m/s for the moving car. This may indicate that the angle mentioned in the question is relative to the ground or horizontal rather than the
  • #1
devanlevin
a man driving his car on a straight road at 25m/s looks through his side windows and sees rain fallling at 30 degrees. when he stops he sees the rain is actually falling straight down(0 degrees).
what is the velocity of the rain, relative to the car
a- when the car is moving
b- when the car is stopped

i said, since the car is driving, it is giving the rain Vx=25m/s (relative to the car) and since i know the angle is 30 degrees

a)
sin30=(Vx)/V
V=25/sin30
V=50m/s

b)
cos30=Vy/v
Vy=50*cos30
vy=43.301

but the answer in my textbook says that the rains velocity is 25m/s for question b) and 28.86 for a)
 
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  • #2


lol how about...

switch the sin and cos in both questions :p.

So use cos in the a)
and sin in b)
 
  • #3


haha, works,
but wouldn't that mean that he sees the rain falling at 60 degrees??
 
  • #4


I think the question means 30 degrees, relative to the ground or the horizontal, rather than the vertical.
 

1. How does the velocity of a moving car affect the rate of rainfall?

The velocity of a moving car does not affect the rate of rainfall. Rainfall is determined by factors such as atmospheric conditions and cloud formation, not by the movement of a car.

2. How does the acceleration of a car impact the trajectory of falling raindrops?

The acceleration of a car does not impact the trajectory of falling raindrops. Raindrops are affected by the force of gravity and air resistance, not by the movement of a car.

3. Can the speed of a car affect the distance between raindrops?

No, the speed of a car does not affect the distance between raindrops. The distance between raindrops is determined by the atmospheric conditions and the size of the raindrops themselves.

4. Can a car's motion cause raindrops to fall at an angle?

No, a car's motion cannot cause raindrops to fall at an angle. Raindrops fall straight down due to the force of gravity, regardless of any external factors such as a moving car.

5. How does the movement of a car affect the time it takes for rain to hit the ground?

The movement of a car does not affect the time it takes for rain to hit the ground. Rainfall is determined by factors such as the size and speed of the raindrops, not by the movement of a car.

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