(a) 1200 rad/s
The angular acceleration of the rotor is given by:
![\alpha = \frac{\omega_f - \omega_i}{t}](https://tex.z-dn.net/?f=%5Calpha%20%3D%20%5Cfrac%7B%5Comega_f%20-%20%5Comega_i%7D%7Bt%7D)
where we have
is the angular acceleration (negative since the rotor is slowing down)
is the final angular speed
is the initial angular speed
t = 10.0 s is the time interval
Solving for
, we find the final angular speed after 10.0 s:
![\omega_f = \omega_i + \alpha t = 2000 rad/s + (-80.0 rad/s^2)(10.0 s)=1200 rad/s](https://tex.z-dn.net/?f=%5Comega_f%20%3D%20%5Comega_i%20%2B%20%5Calpha%20t%20%3D%202000%20rad%2Fs%20%2B%20%28-80.0%20rad%2Fs%5E2%29%2810.0%20s%29%3D1200%20rad%2Fs)
(b) 25 s
We can calculate the time needed for the rotor to come to rest, by using again the same formula:
![\alpha = \frac{\omega_f - \omega_i}{t}](https://tex.z-dn.net/?f=%5Calpha%20%3D%20%5Cfrac%7B%5Comega_f%20-%20%5Comega_i%7D%7Bt%7D)
If we re-arrange it for t, we get:
![t = \frac{\omega_f - \omega_i}{\alpha}](https://tex.z-dn.net/?f=t%20%3D%20%5Cfrac%7B%5Comega_f%20-%20%5Comega_i%7D%7B%5Calpha%7D)
where here we have
is the initial angular speed
is the final angular speed
is the angular acceleration
Solving the equation,
![t=\frac{0-2000 rad/s}{-80.0 rad/s^2}=25 s](https://tex.z-dn.net/?f=t%3D%5Cfrac%7B0-2000%20rad%2Fs%7D%7B-80.0%20rad%2Fs%5E2%7D%3D25%20s)
Answer:
Label A: Battery, Label B: Light or Bulb, Label C: Switch
Explanation:
I got it right.
A. Is very attractive. If it's sublimation directly from water vapor in the air to ice on the glass, then yes. But from liquid water mist to water ice, no. Ice is less dense than water. That's why cubes float in your soda. Better leave 'A' alone. . . . D. Ice pellets turn to liquid. That one's good.
Answer:
88.2 C
Explanation:
The current can be defined as the rate of flow of charge in a conductor.
The relation between charge current and time is given as
I = Q/T
I = current, Q= charge and T = time
that is ampere = coulomb / second
The amount of charge passed is from the negative to the positive terminal
shall be given by:
Q = I * t = 3.5mA * 7h * 3600s/h = 88.2 C
Note: take care of the units.
Answer:
Both, potential energy and kinetic energy depends on mass. The higher the mass, the higher the energy. However, the difference is that potential energy depends on vertical height whereas kinetic energy depends on the velocity.
Explanation:
From the formula we can see that;
Potential Energy = mass* gravitational acceleration *vertical height.
Kinetic Energy = 0.5 * mass * (velocity)^2