(a) 1200 rad/s
The angular acceleration of the rotor is given by:

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:

(b) 25 s
We can calculate the time needed for the rotor to come to rest, by using again the same formula:

If we re-arrange it for t, we get:

where here we have
is the initial angular speed
is the final angular speed
is the angular acceleration
Solving the equation,

I think the correct answer would be to electrolyze water (run an electric current through it) to decompose it into hydrogen and oxygen. Assuming 100% efficiency, it is said that it needs about 40kWh per kilogram of water to fully decompose it.
Answer: Volume of a gas is inversely proportional to pressure of that gas in any container.
Explanation:
Hi, according to Boyle's Gas law, the volume of a gas is inversely proportional to the pressure of that gas, at a constant temperature.
The expression is:
P1.V1= P2.V2
V= 1/P
PV = k
Where:
P = pressure of a gas
V = volume of a gas
k = constant
Feel free to ask for more if needed or if you did not understand something.
The ground exerts an equal force on the golf ball