Answer:
(a) Yes
(b) 102.8 ft
Explanation:
(a)First let convert mile per hour to feet per second
30 mph = 30 * 5280 / 3600 = 44 ft/s
The time it takes for this driver to decelerate comfortably to 0 speed is
t = v / a = 44 / 10 = 4.4 (s)
given that it also takes 1.5 seconds for the driver reaction, the total time she would need is 5.9 seconds. Therefore, if the yellow light was on for 4 seconds, that's not enough time and the dilemma zone would exist.
(b) At this rate the distance covered by the driver is
Since the intersection is only 60 feet wide, the dilemma zone must be
162.8 - 60 = 102.8 ft
Answer:
False ( B )
Explanation:
considering that the wind turbine is a horizontal axis turbine
Power generated/extracted by the turbine can be calculated as
P = n * 1/2 *<em> p</em> *Av^3
where: n = turbine efficiency
<em>p = air density </em>
<em> </em>A = πd^2 / 4
v = speed
From the above equation it can seen that increasing the Blade radius by 10% will increase the Blade Area which will in turn increase the value of the power extracted by the wind turbine
Answer:
-35 degrees F
When mixed in equal parts with water (50/50), antifreeze lowers the freezing point to -35 degrees F and raises the boiling temperature to 223 degrees F. Antifreeze also includes corrosion inhibitors to protect the engine and cooling system against rust and corrosion.
A single car has about 30,000 parts, counting every part down to the smallest screws
Answer:
389.6 W/m²
Explanation:
The power radiated to the surroundings by the small hot surface, P = σεA(T₁⁴ - T₂⁴) where σ = Stefan-Boltzmann constant = 5.67 × 10⁻⁸ W/m²-K⁴, ε = emissivity = 0.8. T₁ = temperature of small hot surface = 430 K and T₂ = temperature of surroundings = 400 K
So, P = σεA(T₁⁴ - T₂⁴)
h = P/A = σε(T₁⁴ - T₂⁴)
Substituting the values of the variables into the equation, we have
h = 5.67 × 10⁻⁸ W/m²-K⁴ × 0.8 ((430 K )⁴ - (400 K)⁴)
h = 5.67 × 10⁻⁸ W/m²-K⁴ × 0.8 (34188010000 K⁴ - 25600000000 K⁴)
h = 5.67 × 10⁻⁸ W/m²-K⁴ × 0.8 × 8588010000K⁴
h = 38955213360 × 10⁻⁸ W/m²
h = 389.55213360 W/m²
h ≅ 389.6 W/m²
