120n
since the speed is doubled, her force is doubled
Answer:
the same stones distance will be condtant .
so option no E
Oh my lord lol I was do ready to help then I saw numbers
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
![P = \frac{1}{2} \rho v^3 A C_p](https://tex.z-dn.net/?f=P%20%3D%20%5Cfrac%7B1%7D%7B2%7D%20%5Crho%20v%5E3%20A%20C_p)
where
is the air density, v = 8.89 m/s is the wind speed, A is the swept area and
is the efficiency
![10000 = 0.5 * 1.2 * 8.89^3 * A * 0.45](https://tex.z-dn.net/?f=10000%20%3D%200.5%20%2A%201.2%20%2A%208.89%5E3%20%2A%20A%20%2A%200.45)
![10000 = 190A](https://tex.z-dn.net/?f=10000%20%3D%20190A)
![A = 10000 / 190 = 52.7 m^2](https://tex.z-dn.net/?f=A%20%3D%2010000%20%2F%20190%20%3D%2052.7%20m%5E2)
The swept area is a circle with radius r being the blade length
![\pi r^2 = A = 52.7](https://tex.z-dn.net/?f=%5Cpi%20r%5E2%20%3D%20A%20%3D%2052.7)
![r^2 = 52.7 / \pi = 16.79](https://tex.z-dn.net/?f=r%5E2%20%3D%2052.7%20%2F%20%5Cpi%20%3D%2016.79)
![r = \sqrt{16.79} = 4.1 m](https://tex.z-dn.net/?f=r%20%3D%20%5Csqrt%7B16.79%7D%20%3D%204.1%20m)
Answer:
v = 0
Explanation:
This problem can be solved by taking into account:
- The equation for the calculation of the period in a spring-masss system
( 1 )
- The equation for the velocity of a simple harmonic motion
( 2 )
where m is the mass of the block, k is the spring constant, A is the amplitude (in this case A = 14 cm) and v is the velocity of the block
Hence
![T = \sqrt{\frac{2 kg}{50 N/m}} = 0.2 s](https://tex.z-dn.net/?f=T%20%3D%20%5Csqrt%7B%5Cfrac%7B2%20kg%7D%7B50%20N%2Fm%7D%7D%20%3D%200.2%20s)
and by reeplacing it in ( 2 ):
![v = \frac{2\pi }{0.2s}(14cm)sin(\frac{2\pi }{0.2s}(0.9s)) = 140\pi sin(9\pi ) = 0](https://tex.z-dn.net/?f=v%20%3D%20%5Cfrac%7B2%5Cpi%20%7D%7B0.2s%7D%2814cm%29sin%28%5Cfrac%7B2%5Cpi%20%7D%7B0.2s%7D%280.9s%29%29%20%3D%20140%5Cpi%20%20sin%289%5Cpi%20%29%20%3D%200)
In this case for 0.9 s the velocity is zero, that is, the block is in a position with the max displacement from the equilibrium.