Answer:
0.233
Explanation:
Given that
Diameter of rotor, d = 40 m
Power of rotor, P = 90 kW
Speed of the wind, v = 8 m/s
Density of air, p = 1.2 kg/m³
It is a known fact that
KE = ½mv², where mass flow rate, m
m = p.A.v, where Area, A
A = πd²/4
A = (3.142 * 40²)/4
A = 3.142 * 1600/4
A = 3.142 * 400
A = 1256.8 m², substitute for A in the mass flow rate equation
m = p.A.v
m = 1.2 * 1256.8 * 8
m = 12065.28, substitute for m in the KE equation
KE = ½mv²
KE = ½ * 12065.28 * 8²
KE = 12065.28 * 32
KE = 386088.96 W or
KE = 386.1 kW
Fraction of kinetic energy converted to electric energy is
Fraction = Electric Power / Total KE
Fraction = 90 / 386.1
Fraction = 0.233
Answer:
b
Explanation:
see how far the bullet goes
q = 1156363.6W/m².
To calculate the heat flux per unit area (W/m²) of a sheet made of metal:
q = -k(ΔT/Δx)
q = -k[(T₂ - T₁)/Δx]
Where, k is the thermal conductivity of the metal, ΔT is the temperature difference and Δx is the thick.
With Δx = 11 mm = 11x10⁻³m, T₂ = 350°C and T₁ = 110°C, and k = 53.0 W/m-K:
q = -53.0W/m-K[(110°C - 350°C)/11x10⁻³m
q = 1156363.6W/m²
Answer:
(a)0.531m/s
(b)0.00169
Explanation:
We are given that
Mass of bullet, m=4.67 g=
1 kg =1000 g
Speed of bullet, v=357m/s
Mass of block 1,
Mass of block 2,
Velocity of block 1,
(a)
Let velocity of the second block after the bullet imbeds itself=v2
Using conservation of momentum
Initial momentum=Final momentum
Hence, the velocity of the second block after the bullet imbeds itself=0.531m/s
(b)Initial kinetic energy before collision
Final kinetic energy after collision
Now, he ratio of the total kinetic energy after the collision to that before the collision
=
=0.00169
