First let's convert everything into SI units.
The length of the blade is 3 inches. Keeping in mind that 1 inc=0.025 m, we have

The angular speed is 600 revolutions per minute. Keeping in mind that

and

, the angular speed becomes

And so, the linear velocity of the edge of the blade is equal to
Answer:
hi there!!
Explanation:
Nickel 149 pm
Cobalt 152 pm
Calcium 194 pm
Potassium 243 pm
So Potassium is the correct answer
In pounds your answer is 15.4324 or 15.4