Answer:
4.1 m
Explanation:
10 kW = 10000 W
20mi/h = 20*1.6 km/mi = 32 km/h = 32 * 1000 (m/km) *(1/3600) hr/s = 8.89 m/s
The power yielded by the wind turbine can be calculated using the following formula
where 
is the air density, v = 8.89 m/s is the wind speed, A is the swept area and 
is the efficiency
The swept area is a circle with radius r being the blade length
soy de texas, united states
Answer:
Wavelength of the sound wave that reaches your ear is 1.15 m
Explanation:
The speed of the wave in string is
where T= 200 N is tension in the string , 
=1.0 g/m is the linear mass density
Wavelength of the wave in the string is
The frequency is
The required wavelength pf the sound wave that reaches the ear is( take velocity of air v=344 m/s)
<u>Answer:</u>
The spinning of the earth around its own axis causes day and night.
<u>Explanation:</u>
Earth has two types of motions. It spins around its own axis causing day and night every 12 hours and completes a rotation in 23.93 hours that make a full day. The part of the earth that faces sunlight during spinning experiences day and the other part has night. It also rotates around the sun and completes one rotation in 365 days that makes a year.
