Answer:a
Explanation:
We have to lift the load two loads up one story, so energy required is
let m be the mass of each load and h is the height of each story
Energy
Here energy gained is the potential energy which depends upon the datum(floor).
For lifting one load up one story
Energy required
thus is half of
So option a is correct
The air pressure inside the balloon is: 0.1432 Pa
The formulas and procedures that we will use to solve this problem are:
Where:
Information about the problem:
Using the formula of the sphere area we get:
a = 4 * π * r²
a = 4 * 3.1416 * (5.0 m)²
a = 314.16 m²
Applying the pressure formula we get:
P = F/a
P = 45 N/314.16 m²
P = 0.1432 Pa
<h3>What is pressure?</h3>It is a physical quantity that expresses the force applied on the area of a surface.
Learn more about pressure at: brainly.com/question/26269477
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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.