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:
d = 69 .57 meter
Explanation:
First case
Speed of car ( v ) = 20.5 mi/h = 9.164 M/S
distance ( d ) = 11.6 meter ( m = mass of the car )
Work done = 0.5 m v² = 0.5 * 9.164² * m J = 41.99 m J
Force = ( workdone /distance ) = ( 41.99 m / 11.6 ) = 3.619 m N
Second case
v = 50.2 mi/h = 22.44135 m/s
d = ?
Work done = 0.5 * 22.44² * m J = 251.7768 * m J
Since the braking force remains the same .
3.619 m = ( 251.7768 m / d )
d = 69 .57 meter
A) Net horizontal force:
Fx= -35 + 25 + -10N
Net vertical force
Fy= 50 - 35 = 15N
Net force
F^2 = fX^2 +Fy^2
F= 18N
B.) Acceleration of system
a=18/5=3.6m/s^2
C). Equilibriant force must be equal to the net force above
F1= 18N
D.) Acceleration becomes half
a1= a/2 =1.8m/s^2
E.) Equilibrant force also doubles
F" = 2F' = 36N
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The answer is downwards because the ball is pulling down the spring due to its weight
It is important to have the international system of units 'cause <span>it can be used by scientists everywhere around the world, and they will be able to understand each other with more accuracy.
In short, Your Answer would be Option D
Hope this helps!</span>
