Answer:
22/0.50=44
Explanation:
average speed= distance / time
First of all, we need to convert the angular speed from rev/min into rev/s:
![\omega_f=300 rev/min=5 rev/s](https://tex.z-dn.net/?f=%20%5Comega_f%3D300%20rev%2Fmin%3D5%20rev%2Fs%20)
The angular acceleration is the variation of angular speed divided by the time:
![\alpha=\frac{\omega_f-\omega_i}{t}=\frac{5 rev/s-0}{2 s}=2.5 rev/s^2](https://tex.z-dn.net/?f=%20%5Calpha%3D%5Cfrac%7B%5Comega_f-%5Comega_i%7D%7Bt%7D%3D%5Cfrac%7B5%20rev%2Fs-0%7D%7B2%20s%7D%3D2.5%20rev%2Fs%5E2%20%20%20)
And this is constant, so we can use the following equation to calculate the angle through which the engine has rotated:
![\theta(t)=\frac{1}{2}\alpha t^2 =\frac{1}{2}(2.5 rev/s^2)(2 s)^2=5 rev](https://tex.z-dn.net/?f=%20%5Ctheta%28t%29%3D%5Cfrac%7B1%7D%7B2%7D%5Calpha%20t%5E2%20%3D%5Cfrac%7B1%7D%7B2%7D%282.5%20rev%2Fs%5E2%29%282%20s%29%5E2%3D5%20rev%20%20%20)
so, 5 revolutions.
True,
Explanation: because it’s the same reason that lighting touches the ground/ goes up to the sky, because it is trying to balance out its charges
The force is -12,000 N
Explanation:
First of all, we calculate the acceleration of the ball, by using the following suvat equation:
![v^2-u^2=2as](https://tex.z-dn.net/?f=v%5E2-u%5E2%3D2as)
where:
v = 0 is the final velocity of the baseball (it comes to rest)
u = 40 m/s is the initial velocity
a is the acceleration
s = 2.0 cm = 0.02 m is the displacement of the ball
Solving for a,
![a=\frac{v^2-u^2}{2s}=\frac{0-40^2}{2(0.02)}=-40,000 m/s^2](https://tex.z-dn.net/?f=a%3D%5Cfrac%7Bv%5E2-u%5E2%7D%7B2s%7D%3D%5Cfrac%7B0-40%5E2%7D%7B2%280.02%29%7D%3D-40%2C000%20m%2Fs%5E2)
Now we can calculate the average force exerted on the ball, by using Newton's second law:
![F=ma](https://tex.z-dn.net/?f=F%3Dma)
where
m = 300 g = 0.3 kg is the mass of the ball
is the acceleration
Substituting,
![F=(0.3)(-40,000)=-12,000 N](https://tex.z-dn.net/?f=F%3D%280.3%29%28-40%2C000%29%3D-12%2C000%20N)
where the negative sign indicates that the direction of the force is opposite to the direction of motion of the ball.
Learn more about forces:
brainly.com/question/8459017
brainly.com/question/11292757
brainly.com/question/12978926
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