Answer:
The police car is moving at 41.24 m/s.
Explanation:
To find the speed of the police car we need to use the Doppler equation:
Where:
v: is the speed of the sound = 343 m/s
: is the speed of the receiver = 12 m/s
: is the speed of the source =?
f: is the observed frequency = 959 Hz
f₀: is the emitted frequency = 1038 Hz
Both terms are positive in the fraction because the velocity of the sound is in the opposite direction to both velocities of the police car and the other car.
By solving the above equation for we have:
Therefore, the police car is moving at 41.24 m/s.
I hope it helps you!
Answer:
W = (F1 - mg sin θ) L, W = -μ mg cos θ L
Explanation:
Let's use Newton's second law to find the friction force. In these problems the x axis is taken parallel to the plane and the y axis perpendicular to the plane
Y Axis
N - 
=
N = W_{y}
X axis
F1 - fr - Wₓ = 0
fr = F1 - Wₓ
Let's use trigonometry to find the components of the weight
sin θ = Wₓ / W
cos θ = W_{y} / W
Wₓ = W sin θ
W_{y} = W cos θ
We substitute
fr = F1 - W sin θ
Work is defined by
W = F .dx
W = F dx cos θ
The friction force is parallel to the plane in the negative direction and the displacement is positive along the plane, so the Angle is 180º and the cos θ= -1
W = -fr x
W = (F1 - mg sin θ) L
Another way to calculate is
fr = μ N
fr = μ W cos θ
the work is
W = -μ mg cos θ L
Given that
Velocity of missile (v) = 20 m/s ,
Angle of missile (Θ) = 53°
Determine , Vertical component = v sin Θ
= 20 sin 53°
= 15.97 m/s
If <em>the isotherms</em> are spaced closely together over some portion of the map, there is a drastic temperature change over that portion.
