Answer:
a) 
b)
Explanation:
Let´s use Doppler effect, in order to calculate the observed frequency by the byciclist. The Doppler effect equation for a general case is given by:
where:
Now let's consider the next cases:
The data provided by the problem is:
The problem don't give us aditional information about the medium, so let's assume the medium is the air, so the speed of sound in air is:
Now, in the first case the observer alone is in motion towards to the source, hence:
Finally, in the second case the observer alone is in motion away from the source, so:
Hi there!
Since the crate is being slid at a constant speed, the forces sum to 0 N. In this instance, the following forces occur in the axis of interest:
Wsinθ = downward acceleration along incline due to gravity (N)
Fκ = kinetic friction force along incline (N)
A = applied force (N)
The acceleration due to gravity and friction force act in the same direction, so:
Wsinθ + Fκ = A
Solve for sinθ using right triangle trigonometry:
sinθ = O/H = 3/6 = 0.5
Rearrange the equation for the force of kinetic friction and solve:
Fκ = A - 0.5W
Fκ = 30.4 - 20 = 10.4 N
Now, recall that:
Work = Force × displacement (W = F × d)
Since the box's displacement is in the same axis as the force but OPPOSITE direction, we must use:
W = Fdcosθ
Angle between displacement and friction force is 180°.
cos(180) = -1
Work done by friction = -Fd = -10.4(6) = -62.4 J
Answer:
C. 10⁻³ rads
Explanation:
Here, we shall use Rayleigh's Criterion to find out the angular resolution of Cat's eye during day light. Rayleigh's Criterion is written as follows:
θ = λ/a
where,
θ = angular resolution of Cat's eye = ?
λ = wavelength = 500 nm = 5 x 10⁻⁷ m
a = slit width of eye = 0.5 mm = 5 x 10⁻⁴ m
Therefore,
θ = (5 x 10⁻⁷ m/5 x 10⁻⁴ m)
Therefore,
θ = 0.001
θ = Sin⁻¹(0.001)
θ = 0.001 rad = 1 x 10⁻³ rad
Hence, the correct answer is:
<u>C. 10⁻³ rads</u>
Answer:
55kmh
Explanation:
first of all according to formula add both of the velocity and divide it by 2
