Answer:
The free end of the blade has a tangential velocity of about 88.19 m/s
Explanation:
The angular velocity of the blades is 
since the blades are 80 m long, then the tangential velocity of the free end of the blade is:

|Momentum| = (mass) x (speed)
225 kg-m/s =(50kg) x (speed)
Divide each side by (50kg): Speed=(225 kg-m/s) / (50 kg) = 4.5 m/s .
Regarding the velocity, nothing can be said other than the speed, because
we have no information regarding the direction of the object's motion.
The most exact answer is 78.4J also in this kind of options we can say answer "d"
<span>Interference can only be explained if light is a wave. Youngs Double Slit experiment proved this, proving the wave nature of light.</span>
Like they said the leopard seal will overpopulate and kill out all of the other animals. Because it would be at the top of the chain then without the killer whale. Therefore, since it is at the top of the chain it will overpopulate because it has nothing to eat/kill it so then they would eat the animals lower than them<span />