Solution :
Given
Diameter of the roulette ball = 30 cm
The speed ball spun at the beginning = 150 rpm
The speed of the ball during a period of 5 seconds = 60 rpm
Therefore, change of speed in 5 seconds = 150 - 60
= 90 rpm
Therefore,
90 revolutions in 1 minute
or In 1 minute the ball revolves 90 times
i.e. 1 min = 90 rev
60 sec = 90 rev
1 sec = 90/ 60 rec
5 sec = 
= 75 rev
Therefore, the ball made 75 revolutions during the 5 seconds.
Answer:
Some elements are reactive because the outermost energy levels of their atoms are only partially filled. Therefore, these atoms can easily gain or lose electrons to form ions. The atoms of nonreactive elements have filled outermost energy levels
Explanation:
hope this answers your ?
The answer is A. Urinary system
All it does is lets him pull in a more convenient direction to raise the load. It has no effect on the required force.