The correct answer to the question is: A) miles/hour and B) metre/ second.
EXPLANATION:
Before answering this question, first we have to understand speed.
The speed of a body is defined as the rate of distance travelled or the distance travelled by a body per unit time.
Hence, it is a derived quantity which is obtained from distance and time.
The unit of distance can be metre, miles, and the unit of time can be second, minutes or hour.
As speed is the distance covered per unit time, the perfect units will be miles/hour and metre/second.
Hence, the correct options are first and second.
Explanation:
We know that that the range of the ball on the earth

therefore, range of the ball on moon


therefore,

Therefore, the range of ball will be 6 times on the moon than that on earth
For pressurized water reactors the coolant is not permitted to boil in the core of the PRW, however the coolant in boiling water reactors is permitted to do so in the core of BWR. Pressurized water reactors have an indirect cycle. Whereas, the boiling water reactors go through a direct cycle. Both are light water reactors.
Explanation:
potential energy = mass × gravity force × height
=20 × 10 × 25
= 5000 joules