When an item is raised, the work is done in opposition to gravity. When an item is worked on, energy is transmitted to it, and it develops gravitational potential energy. If the same thing falls from that height, gravity must do the same amount of effort to bring it back to the Earth's surface.
Answer:
Time= 6.12*10^4s
mass flow rate m=0.98kg/s
Explanation:
Given
Volume= 60m^3
diamter= 2.5cm= 0.025m
radius= 0.0125m
area A= πr^2
area A= 3.142*0.0125^2
area A= 4.9*10^-4m^2
the velocity of the flow 2m/s
<u>volume flow rate </u>
V=vA
V=2* 4.9*10^-4
V=9.82*10^-4 m^3/s
<u>Time taken to fill the pool</u>
time= volume/volume flow rate
time= 60/9.82*10^-4
time= 6.12*10^4s
<u>Mass flow rate </u>
m= density *volume flow rate
Assuming the density of water to be 997kg/m^3
m= 997*9.82*10^-4
m=0.98kg/s
Answer:
b
i remember this question from when i had a test to take.
The car's speed was zero at the beginning of the 12 seconds,
and 18 m/s at the end of it. Since the acceleration was 'uniform'
during that time, the car's average speed was (1/2)(0 + 18) = 9 m/s.
12 seconds at an average speed of 9 m/s ==> (12 x 9) = 108 meters .
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That's the way I like to brain it out. If you prefer to use the formula,
the first problem you run into is: You need to remember the formula !
The formula is D = 1/2 a T²
Distance = (1/2 acceleration) x (time in seconds)²
Acceleration = (change in speed) / (time for the change)
= (18 m/s) / (12 sec)
= 1.5 m/s² .
Distance = (1/2 x 1.5 m/s²) x (12 sec)²
= (0.75 m/s²) x (144 sec²) = 108 meters .
